They won't look upon other suggies as relatives, they will just become colony members. If males are not neutered they will breed with females whether they are related or un related.
There is no guarantee that just because they are related they will get along indefinately, like all colonies there will be squabbles and at some point, you could be faced with the fact that someone is being bullied and possible even kicked out of the colony.
If you want a large colony, just make sure the enclosure is as big as possible, that there are plenty of hiding places, nest boxes/pouches, and food and water stations.
A colony is (in my opinion) more interesting to watch as they interact more with each other as gliders, but you do need to be extra vigilant and make sure everyone is getting along

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