firehouse primary
n.— «In a firehouse primary, a limited number of voting locations are chosen within a legislative district and ballots are cast on one day within a set amount of time, usually shorter than a regularly scheduled election. The party that chooses a firehouse primary is also responsible for organizing, staffing and monitoring such an election.» —“Rare, intraparty primary challenges both set for June 12″ by Todd Jackson Roanoke Times (Virginia) Mar. 8, 2007. (source: Double-Tongued Dictionary)