Why There would be two benefits to doing this asap: a) In balance testing, it would be handy to be able to restrict what can be built so for example you could test in isolation how T1 land bots fare against T1 vehicles, etc etc. Pairwise comparisons are useful. b) Opens up huge amounts of variety in the types of game you can setup (nukes only, anyone? t1 air only? heh heh) How Nicest implementation would be a 'treeview' control basically, with checkboxes at each level. So you could tick at a higher level to toggle that whole category on/off, and then adjust any exceptions you want at the lower levels. ie Air [ ] T1 [ ] Factory [ ] Unit 1 [ ] T2 [ ]... Naval Land Orbital Special etc