For the current round of reorganization, Belfast city was always considered as a unit on its own, but the other districts were to be grouped into 6, 10 or 14 clusters depending on the model being used. While the populations are meant to be approximately equal, there's no strict limit.
apart from that, what is the reasoning for merging Derry and Strabane (not that merging it with Limavady makes much more sense
and why have they merged some of Castlereagh into Belast but left three random bits out? surely move all of the built up area in to Belfast and merge the rest into Ards
