All four played against England at the start of the month, but were dropped from Frank Hadden's 22-man squad altogether for the Wales game a week later.
Glasgow coach Sean Lineen said: "It is both disappointing and encouraging to have so many current Scotland internationals available.
"But what has been good is that they have come back with the right attitude and have a point to prove.
"How they react is up to them. They can just accept that they will not be involved next week or they can also say to themselves that if they play really well against a quality team then they are making it hard for Frank to leave them out – they can really hold their hands up.
"I think Frank will look at it that way as well. He will take into account the character of the player, whether he goes away and sulks, or what he does to get back in.
"I have had a good chat with them all, and have been really impressed with their attitude – the enthusiasm they have shown and the determination."