When you introduce them in neutral territory, have a clean (or new) pouch for them to go into if they seem to be OK with each other. If they settle down and sleep together, then put them (in the pouch) into a freshly cleaned cage and let them finish their day's sleep together.
Be sure to feed them before they wake up and put food in several different locations in the cage so there is no way one glider can chase the other away from all of the food dishes.
You might put the cage where you can hear them the first night or so, but if they are willing to sleep together for the day - they will probably be fine together when they wake up.
If they do fight when you put them together, or when they wake up, then separate them and start the pouch and toy swapping again and try again in a week or so. Be patient, they can learn to love each other, it just might take a few tries.