Under the American Bar Association’s Model Rule 7.2, a lawyer may agree with another lawyer or a nonlawyer professional to send each other clients. Two conditions apply. The “reciprocal referral agreement is not exclusive,” and “the client is informed of the existence and nature of the agreement.”
A comment to the rule adds that such an agreement “must not interfere with the lawyer’s professional judgment as to making referrals.” The same comment advises lawyers not to make these arrangements for an indefinite time.