I wouldent put them together untill the babies are weaned. Because A: Even if the females know eachother, the one that has babies now may still look at her like a theat, and B: They WILL fight over the babies. I had two together (I didn't know the one was preggers and it was a big cage, plus they were together before the first one gave birth), then suddenly the other girl had a litter. They kept to their corners though, so I left them together for a little bit. But I had to seperate them within a week, because there was a total of 25 babies, and they both wanted ALL of the babies to themselves. I finally seperated them after thay had a tug-o-war match wth a baby! Luckily though, the baby was OK, but no- don't put them together till after all babies are weaned.