Here's what I imagine is a common fact pattern in a legal ethics class regarding disqualification. (Something similar certainly showed up in mine.) Lawyer A works for Firm X, who represents Company M in a case. Lawyer A, however, is a low-ranking associate who had nothing to do with the Company M case. He then leaves the firm for Firm Y, who starts representing Company K in a case against M, relatively the same matter as Firm X works on for Company M. Firm Y--which didn't know about this possible conflict of interest when they hired this young fellow--immediately makes certain that the files on K v. M are hidden from young Lawyer A, makes sure that he's not involved in the case, and no one talks to him about it. Nevertheless, Firm X and Company M bring a motion to disqualify Firm Y.
I'll not address the legal question, which most law students will get to at some point and would bore my non-legal readers to death. Instead, I had a good laugh looking at the legal history of what you call the isolation process that Firm Y goes through to cut off Lawyer A.
The most common term is probably the erection of a "Chinese Wall." Makes sense, one would suppose: the Great Wall of China was certainly taken seriously by those who constructed it, worked reasonably well to keep things on one side or the other, and is famous enough that most people will get the reference.
But the term wasn't politically-correct enough for California courts. Indeed, at least one judge in the First Appellate District of California damned the term for having "an ethnic focus which many would consider a subtle form of linguistic discrimination." See Peat, Marwick, Mitchell & Co. v. Superior Court, 200 Cal. App. 3d 272, 293 (1988) (Low, P.J., concurring). The Northern District of California agreed. See Employers Insurance of Wausau v. Albert D. Seeno Construction Co., 692 F.Supp 1150, 1165 (1988). The court opted for the considerably duller but possibly less inflammatory "ethical wall."
On the other hand, the key case in our textbook, Nemours Foundation v. Gilbane, 632 F.Supp. 418 (N.D.Del. 1986), takes a completely different view. Opining that the ethical obligation lies with the individual attorney, it opts for the term "cone of silence." An interesting ethical debate rages between these courts as to exactly how this metaphor fits in with the ethical rules, but I couldn't read it without giggling.
After all, the Delaware court decided to get its symbolism from the 1960's spy spoof Get Smart!. In so doing, the judge opines that "the more logically consistent, honest, and straightforward approach is to credit members of the legal profession with a certain level of integrity." How can one do that while envisioning Don Adams and Barbara Feldon beneath a cheap plastic canopy of a stage prop? And besides, as my textbook points out and my memory confirms, the cone of silence was notoriously unreliable.
Ah well. Perhaps the judge felt that the legal profession is of insufficient interest to the agents of KAOS.
: (UPDATE) Actually, I think the term is more apt than the Peat, Marwick court gives it credit. After all, the Chinese Wall is rarely used as a term of disrespect, is generally put forward in order to convince people of its sturdiness, and at least makes a plausible historical fit. Certainly better than calling condoms Trojans, which has never made a lot of sense to me, given that their defenses were most notable for being breached.