In the single player campaign you can only have one RTS battle per turn, and only assign each general to one battle when auto-resolving.
For multi-player I can see wanting to limit the number of RTS battles, but I think each player would have to be given an opportunity to chose one battle to do manually, otherwise you could have two home countries invaded in the same turn, which neither party would want to auto-resolve if they left it relatively unguarded.
There was talk at one point of the possibility a multi-player mode of just the strategy map part of the game (no RTS combat), but I don't know if it will be included.
