Is it permissible for a man to have sex with 2 or 3 wives at a time if his wives have no problem to have sex and have no problem to share their husband together?
Note that, they are wives, not hired women.
All Praise to Allah Swt and blessings on Prophet Muhammad peace be upon him His family and companions
It was narrated from 'Abdur-Rahman bin Abu Sa'eed Al-Khudri from his father that:
The Messenger of Allah said: "No woman should look at the nakedness of another woman, and no man should look at the nakedness of another man."(Ibn Majah)
And
“A man should not see the private parts of another man, and a woman should not see the private parts of another woman, and a man should not lie with another man under one covering, and a woman should not lie with another woman under one covering” (Sunan Abu Dawud)
It is not allowed for a women to show herself naked to another women except for her husband.She is not supposed to show her awrah to a woman also. It is also not allowed for two Men or Women to share their blanket as it could lead to homosexuality.
It was narrated that Aishah (RA) said:
"The Messenger of Allah used to divide his time equally among his wives, then he would say 'O Allah, this is what I am doing with regard to that which is within my control, so do not hold me accountable for that which is under Your control and is beyond my control.'"(Ibn Majah,Sahih)
Prophet Muhammad kept his wives in a separate houses visiting them on an alternate basis this also shows that group sex is not allowed in Islam.When going on a journey Prophet Muhammad (peace be on him) would cast lots among his wives, and the one who was chosen by lot would accompany him.
Aishah (RA) wife of the Prophet (ﷺ) reported “When the Apostle of Allaah(ﷺ) intended to go on a journey he cast lots amongst his wives and the one who was chosen by lot went on it with him. He divided his time, day and night (equally) for each of his wives except that Saudah daughter of Zam’ah gave her day to A’ishah.(Sunan Abi Dawud,Sahih)
Modesty is a distictive part in our religion.
It was narrated from Ibn ‘Abbas that the Messenger of Allah (ﷺ) said: “Every religion has its distinct characteristic, and the distinct characteristic of Islam is modesty.’”(Ibn Majah)
Allah Swt and His Messenger knows best.
I am not sure of your situation, whether or not you are actually married or you're just asking hypothetical question. First I would say that Allah is all knowing and wise. We have to take account that when Allah wrote the Qur'an, the book was necessary to address the "Times of ignorance" as during that time, men were allowed unlimited wives. You can see how much problems would arise when you are married to many wives.
I think Allah, being all merciful allowed us to have 4 wives because it was his way of compromising with our ignorant practices. To prove this, he says in the Quran:
4:3 And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hand possesses. That is more suitable that you may not incline [to injustice].
There is a condition to polygamy as stated in the Qur' an:
But if you fear that you will not be just, then [marry only] one
We all know that this condition cannot be met (most of the time or in most cases). There are couples that have tried group sex, and find it boring if one persons chemistry is greater than the others. This fantasy may be great for you as a man but a lot of women find that kind of sex uncomfortable, because some women feel left out or jealous.
I find that if you all don't have a "groove" or have great communication, this can get really messy. Do these women have lesbian tendencies? Are they attracted to each other? The reason why I ask is because what will they do when you are pleasuring one woman - are they just going to stand there and wait for their turn?
I find that with this arrangement women are not going to be treated equal, and thus I would advise not to. I think it would be selfish to wish that unless the women are into each other, but then we get into another "can of worms".
*) the Prophet said "what the husband and wife did in the privacy don't tell others "
*) when Quran say women, the book refers to Unmarried women. "No woman should look at the nakedness of another woman", the book did not specially have a case for "Married Muslim women, and Married Muslim women" to the same man.
*) scholars argue that the Prophet Mohamed (peasce be upon him) had some wives who lived separate, and some wifes lived with him in the same house.
*) Quran 2:23 "go to your wives for sex in any manner you choose."
*) if approaching all wifes at the same time. is this not an equally giving of time to all wives. it is exactly equal.
*) "women feel left out or jealousy" women no matter what the case, even if there is 1 wife, she will still have jealousy and envious feelings of other women.
Lesbian and Zina
Since the time of the Ottoman Empire , which was closer to the time of the Quran then our time, there was no known case of women being punished for lesbianism if both women were married to one man. In addition Lesbianism was not considered Zina since women do not have the Phallic, therefore they are physically incapable of doing penetration with each other, therefore is was not considered sex. therefore is not Zina. if not considered sex, it cannot be homosexual. In history homosexuality, focuses more on man man sex which is considered Zina and punishable by death.