I don't know if a military unit would have a say in that, though.

EDIT: I imagine the only way you'd have a say in that without being Klamath would be to play as someone high in the government, or as another state lending assistance for a role in how the annexed territories are handled. At this point, the NCR is made up of loosely unified states that compete, so nothing would be for free. Help would cost something. There is no good will among the states based on patriotism.