[cypher]

I think you need to weigh up the risks against potential benefits tbh, it is possible that the one you had to separate recently might be able to go back into the group but there is also a very high chance of him not being accepted & I do think it's highly unlikely that the one who has been separated for some time would be accepted back into the group.
There is a risk of fighting & not only the reintroduced ham not being accepted but also of the whole group dynamic being upset by the stress & then you may need to separate more of them.
Personally I would say keep the two separate ones alone now & leave the remaining group as it is to avoid the high chance of fighting, injuries & having to rehouse them.