How to introduce two pairs of rats?

[Miss Misery]

Well in a couple months my boyfriend and I are planning to move in together. He has a pair of girl rats and so do I, the only difference is that mine are hairless.
I was hoping they could all live at my house together(My cage is bigger) before the move so it wouldn't be as stressful moving them and then going through intros and all that.
His are kind of skittish and mine are very outgoing and love getting attention, so how do I introduce two completely different pairs of rats without it turning out horribly?

 

[RatLuver]

If you must, introduce them in a place away from what they consider theirs ( cage, food, toys ETC.) Slowly introduce them and keep a close eye on them. If they act aggressively or unsure separate them immediately. Make sure they are disease free or they will get each other sick. PS. Hairless rats get along fine with regular rats and don't know they are different. You just have to be careful of scratches.

 

[Sariel]

There are a variety of ways to go about this but your best bet is to always do it gradually. Start slow and use neutral territory so that it doesn't smell like an area that "belongs" to either pair of rats. Expect a little fighting as they establish a hierarchy and be prepared to separate immediately as necessary.