Dogs are pack animals.. yes.. and no... Dogs are wolves, wolves are not specifically pack animals, they are social as in they live in familly units with the pups of previous litters, but that ends there, older ones are chased away and many are solitary, which is not the same with gliders who do live in colony in the wild and never stay alone for really long, they graft themselves on other colonies or join newly formed groups... That makes the comparison hazardhous.
That being said, some gliders do well by themselves, providing their human spend lots of time with them (which doesnt mean that it is ideal), and from observation, even lone gliders have a totally different behavior once in a group.
For introduction, it is advised that both animals have the same weight/size, and introductions should be made in neutral ground to avoid territorial issues.
Intact males might not necessarily fight providing there is no female in the house, that the introduction is successful and that they are housed in a new cage afterwards (or at least one which has been made odor neutral and in which the items have not been previously claimed by one), especially if they are introduced when young (I've never had issues here, and none of my males are neutered). However, the risk are higher when trying to introduce adults which are more territorials.