Introducing new gliders:  (I changed it to “new” instead of “two”…because there may be more than two lol) To introduce new gliders for whatever reason requires just as much, if not more patience sometimes, than earning trust and bonding.  The most successful methods, are listed below, but keep in mind, that sometimes it just doesn't work out…Introductions may take some time, do NOT try to rush this. This is NOT for colony breeding purposes.
Below are some worse case scenarios that we have read about or experienced.  The risks are high...
1. A glider may die from fighting with a newly introduced glider.
2. A glider may get seriously injured and require medical treatment.
3. A young female glider will get raped by a sexually mature male.
4. A bonded glider doesn't always teach the other to bond.  The bonded glider may dump you for his new mate.
5. A separate cage will be needed and sometimes separate rooms to ensure safety.
6. They may never get along.  Some gliders love being the only one.  Your glider may be set in their ways and resent an intruder.
7. When introducing new gliders keep this thought in mind - You picked their friend for them, how would you react if your parents did that for you, and you didn't like the person?
 What is first???
First try to allow them to play together in a neutral room, one where neither has marked, and that neither has claimed to be theirs.  Be prepared to separate if fighting does break out.  While you try to separate them you will most likely get bitten, and it may be a vicious bite or series of bites.  If this happens, you MUST separate them.  If you must separate them then you will need to follow some or all of the methods below.  If they seem to get along, go to the section called PLACEMENT...
Some things you DON'T want to do...
1. Do not just throw them into an existing cage and hope they get along.  Be sure you have kept them quarantined for 2 weeks prior to any new introductions, or have a thorough exam done by a vet, including feces.
2. Do NOT allow them to fight it out.
3. Never place a baby in with an adult
4. Never place an immature female with a sexually mature male.
5. Do not think getting another glider will calm an aggressive glider.
6. Never place an un neutered adult male in with another adult male.
There are things you can try, but none come with guarantees...
You already know they will fight, don't try putting them together until you see some signs of them at least tolerating each other.  One may KILL the other...It is not worth the life of a glider to find out these things can and MAY happen.
Methods
              a. place their cages near each other, a foot apart.
              b. swap out their beds each night.
              c. swap their toys and food bowls as well.
              d. place a sheet over both cages so they are locked with each
              others scent.
              e. put some vanilla or peppermint extract on each glider before letting
              them out to play, that way, they smell the same..
              f. place their cages in a neutral room, where neither has been.
              g. swap their cages, see how they react to that..
              When you hear them clicking to each other, then you know they
              are talking...LOL much like an old married couple in therapy...LOL
Placement
 I highly suggest when placing the two in the same cage for the first time, to put them into a neutral cage, one that neither has "claimed" as theirs. Place 2  new pouches or nest boxes, 2 water containers, and 2 food bowls at different heights, and opposite sides of the cages, so they can sleep , eat and drink separate in case there is one that is more dominate and won't allow the other to eat, drink or sleep. Do not add toys or clutter the cage, so if need be, you can get to them easier and they have room to avoid each other. Simply washing the items WILL NOT remove all the scents. A faint smell of the glider that used it will remain even after washing. You don't want either glider to feel superior, they both must feel they are actually invading the others territory.  As time goes on, you can slowly start to add toys.  ONLY after you KNOW they have accepted each other. Even after the introduction has taken place, please monitor their weight as well as being absolutely positive that one glider is not stopping the other from eating or drinking. If you see one force the other out of the bowl, chase them off, or one gain more weight than the other, PLEASE add a second feeding station on opposite sides of the cage.