Yes. It's not that you lived there, it's, as you acknowledge, at least some of this debt is rightfully yours, regardless of whose name was on the account.
Maybe you already paid your account-holding roommate your share and he kept the money. Sue him for his share, and sue any other roommates who didn't pay their share, in Small Claims court.
PLEASE READ THIS BEFORE YOU COMMENT, EMAIL ME OR PHONE ME. I'm only licensed in CA. This answer doesn't make me your lawyer, and neither do follow-up comments and/or emails and/or phone calls, and you shouldn't expect me to respond to your further questions if you haven't hired me. We need an actual agreement confirmed in writing before any attorney-client relationship is formed. This answer doesn't constitute legal advice, and shouldn't be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.