Can I safetly move chickens together that know eachother but have never lived together before?

I have 3 hens living indoors right now. 2 of the hens are sisters, and about 7 months old, and were living with their 3 brothers, but the boys started harrassing the girls to such an extent that the girls couldn't get at the food or the water, so, I brought the girls inside until I can get rid of the boys. They were put in a large dog kennel in my spare bedroom about a month ago. The other hen is from my main flock, she's a little over a year old. She had bumblefoot, and was showing signs of a possible respiratory infection, so I brought her into the house about 3 weeks ago, and put her in the 2nd bathroom, in the bathtub. Though she manages to get out of the tub so often, it's more accurate to say she has the run of the bathroom. Her respiratory symptoms cleared up 2 weeks ago, and her bumblefoot surgery appears to have been successful, so I am feeling her health is well on the mend.

The weather outside right now is extremely cold, and I was uncertain about putting any of the 3 outside until it warms up, since they are all acclimated to the warmer indoor temperatures now. Beside, I don't have a free coop for the sisters right now anyway. The 2 girls are starting to go stir crazy in their dog crate though, so I had the thought of possibly trying to introduce them to the one hen in the bathroom. They are from seperate coops, but before winter hit hard both my flocks free ranged together, so they aren't totally new to eachother. And I figured if I could get the 3 friendly, that might help with introductions back into the main flock once the weather warms up. But I won't be home during the day to monitor things, and there isn't really any place in the bathroom for anyone to escape to should things get ugly.

I don't think I'll be able to leave the two in the crate much longer though, and I have nowhere else to put them. Would it be okay to try and introduce the three?

The "adjustment" of the pecking order when the two groups encounter each other could be rather vigorous. I don't think I would especially want to have it going on in my bathroom, especially if I were to come home after being gone all day. I would expect a mess, maybe even some blood from bitten combs, which can be part of the sorting out of the pecking order.

You really want to wait until you can provide plenty of space for this encounter. The confines of a bathroom are not the appropriate venue, unless you plan on redecorating once the chickens are finished with it.

No, there's almost no chance of the encounter being peaceful and uneventful.

I want to thank you for your advice. You pretty much confirmed what I was already thinking. I have decided to move the kennel into the bathroom for now; I'm hoping this might give them a chance to get used to eachother. In a few days I'll bring them out together while I'm around to supervise, and we'll see how things go.