Concurrent conflicts of interest — NY RPC 1.7
A lawyer shall not represent a client if a reasonable lawyer would conclude that either the representation will involve the lawyer in representing differing interests, or there is a significant risk that the lawyer's professional judgment on behalf of a client will be adversely affected by the lawyer's own financial, business, property or other personal interests. Notwithstanding the existence of a concurrent conflict, a lawyer may represent a client if each affected client gives informed consent, confirmed in writing.