Just as one of his premiere K Street properties faces a staff exodus, WPP CEO Sir Martin Sorrell is heading to Washington, D.C., next week for a previously scheduled meeting with top executives from the conglomerate’s shops, according to people familiar with the session.

WPP-owned Ogilvy Government Relations this week said goodbye to four lobbyists, including CEO Drew Maloney and top GOP lobbyist and fundraiser Wayne Berman, who is affiliating with his client, the private equity firm Blackstone Group. Maloney, an adviser to presumptive Republican presidential nominee Mitt Romney, is going to the Republican National Committee.

Capitol Counsel announced Wednesday that it had snagged Ogilvy’s John O’Neill, a one-time policy director and counsel in the Senate Republican Whip’s office when former Sen. Trent Lott (Miss.) held the post. O’Neill also previously worked for the Senate Finance Committee.

Ogilvy’s lobby shop also lost Elena Tompkins, who is expected to start her own shop.

The session with Sorrell — whose WPP holdings in D.C. also include Prime Policy Group, QGA Public Affairs, Glover Park Group and Wexler & Walker Public Policy Associates — is scheduled to take place Wednesday at the Glover Park offices.

A spokesman for Ogilvy did not immediately return a call seeking comment. Berman also did not return a call seeking comment.