In my experience, when building a colony, it's good to have a second cage for mishaps. It doesn't have to be a huge one.
At their ages, you will already have a chain of command, or pecking order. There will already be an alpha.
It's good to do intros, one on one and I recommend a 30 quarantine and 2 vet
visits. One when you get them and just before intros. A urine and fecal done both times.
You don't want the new gliders to bring in something like a sickness or parasite, and then all gliders will have to be treated by a vet