Sorry I misinterpreted your question before.
In my opinion, gliders feel more comfortable when there are others around, and is specially good for bonding if a glider sees another feeling safe around you. Usually the way it works is that there is what I call a "scout" glider in the group, that will be more outgoing and prompt to go around exploring. Once the "scout" signals an "all clear" other gliders will follow and do as he/she did. I know it sounds silly the way I say it, but I am telling you from what I have seen with my gliders. My male, Loki, is the "scout" and whenever there is something new to explore, he'd be the one going out first, while my female, Freyja, stays in the safety of the pouch. Loki would thoroughly explore the new thing, and then go back to Freyja to let her know everything is ok (at least that's what it looks like to me); and after that she will come out of the pouch and happily go frolicking around.
Freyja has always been a very skittish glider, and it was a lot harder to bond with her than with Loki. At some point I even tried to do a 1 on 1 bonding with just her and I, but it went even worse than when Loki was around; so I decided to just continue the bonding process with her and Loki together. Eventually, and with the help of a lot of treats, she bonded to us, and is a very sweet girl, though still very neurotic. And from observing them, I noticed this patter with the 2 of them, and have heard very similar stories as well. So that is why I think that bonding will work better having more than 1 glider at a time, maybe not all 6, but 2 or 3 at beginning should be fine, until eventually you can have them all out with you for play time.