Lawyers often represent multiple clients on the same matter. In those situations, there generally can be no secrets among the jointly represented clients – absent some agreement to the contrary. This distinguishes the joint representation situation from a “common interest” agreement, in which separately represented clients share some (but not all) information as part of a common litigation strategy.
Because generally there can be no secrets among jointly represented clients, any adversity between them usually entitles either client to obtain the files the lawyer generated while representing both of them. The Court in Indiantown Realty Partners v. Brown-Haward, 270 B.R. 532 (Bank. S.D. Fla. 2001) just reiterated this principle.
Lawyers who are invited to represent more than one client on the same matter should remember their duties of disclosure both during the representation and afterwards (especially if adversity might develop between the clients).