Wow. I never knew they were really brothers.
I'm pretty sure he has an occasional recurring role as a defense attorney. The actor who played Beecher is also a recurring defense lawyer, a long-haired type reminiscent of a younger Ron Kuby. And I remember Scott Winters being in Deadline, a series about a newspaper columnist that was one of Dick Wolf's few failures. It starred Oliver Platt as the columnist and Bebe Neuwirth as his editor, and ran about half a season, I think.
In other cross-overs, Lance Reddick, who played an undercover cop-turned-addict-turned-convict on Oz, went on to play an ME on SVU, and now has the lead in The Wire on HBO. Zejlko Ivanek, who played the governor on Oz, was the DA on Homicide, and did several L&O crossovers in that role. Luis Guzman, who was one of the Latino gang leaders on Oz, has had a number of short parts like uniform cop or fire inspector on various L&O shows.
It makes sense, really; two good friends share their rolodexes, and point each other to actors who can come in on short rehearsal and get the scene in one take. Wolf and Fontana recommend actors to each other the way the rest of us might recommend a reliable plumber or lawn guy.