In a department of about 110 mostly chem engineers (maybe 40% with PhDs), the most represented schools are the ones we recruit heavily from, i.e., Rutgers, PSU, Princeton, Delaware, UVA, Michigan, MIT, Cornell, Purdue, and Penn. As you can see, none of our old BE rivals are represented (except one UConn guy, who somehow slipped in) and of the rest about half don't have 1A football, so it's mostly PSU, Michigan, UVA, and Purdue to compete with. And several of the 1AA guys like RU as the local (most aren't from NJ) team and some of them are ticketmates with me.
Most of the smack talk is with PSU/Michigan folks. Luckily my boss is an RU guy and has been going to games with me for 10 years or so. I have a couple of RU guys and a couple of PSU guys in my group - most of the rest are 1AA folks.