Is there any case law where a plaintiff and defendant attorney have a conflict of interest agreement?

Defendant contends that because the attorneys shared investigative services, office space, and support staff, we must conclude that they were not sufficiently independent of each other. Not so. Many sole practitioners share investigative services, office space, and support staff; however, they maintain their own office, phone number, letterhead, pleading paper, and business cards. They hold themselves out as sole practitioners and they keep separate confidential files, none of which are cross-accessible. Moreover, the conflicts contract specifies that the contract may be terminated by an attorney's failure to observe the rules of professional conduct, including rule 3-310. [52 Cal.App.4th 617] Thus, absent any evidence to the contrary, we presume that the attorneys in the instant action maintained sufficient independence from each other and acted ethically when representing each codefendant. (Cf. People v. Christian (1996) 41 Cal.App.4th 986, 1000, 48 Cal.Rptr.2d 867; Castro v. Los Angeles County Bd. of Supervisors (1991) 232 Cal.App.3d 1432, 1442, 284 Cal.Rptr. 154.)