The cross-town schools for Holy Cross are Worcester Polytech (WPI) and Worcester State College - this is on the Holy Cross NROTC website; I don't recall hearing about the other colleges being affiliated, but I'm no expert. My son's NROTC scholarship was to Holy Cross but since he was wait-listed at the school, he transferred to RPI.
This may or may not factor into your decision, but I found out from the commanding officer of the HC unit that each ROTC school handles room and board differently. For example, RPI offers a special school full room and board scholarship to ROTC students but Holy Cross only covers room - board is the responsibility of the student. Villanova doesn't cover either. I never found out about the other ROTC schools he was accepted to.