Republican Members of the Michigan delegation are lining up to help their former colleague, ex-Rep. Pete Hoekstra, fill his Senate campaign coffers.

Almost every Michigan GOP House Member will headline a lunchtime fundraiser for Hoekstra’s campaign on Sept. 19 near Capitol Hill, according to a copy of the invitation obtained by Roll Call.

Hoekstra is the leading GOP candidate to challenge Sen. Debbie Stabenow (D) in 2012, but he’s not the only Republican in the hunt. He’s rolled out a slew of endorsements this summer as his potential primary challengers make noise.

Seven House GOP Members are on the invitation for the high-dollar Hoekstra fundraiser: Reps. Justin Amash, Dan Benishek, Bill Huizenga, Candice Miller, Mike Rogers, Fred Upton and Tim Walberg. At least four of those Republicans have endorsed Hoekstra already — Huizenga, Amash, Miller and Walberg.

Two Republican Members of the delegation are not on the invitation: Reps. Dave Camp and Thaddeus McCotter.