The Wentzville School district is assigning students to different middle schools next fall, directing some to the expanded South Middle School while alleviating overcrowding at Frontier Middle School.

The district has nine elementary schools, three middle schools and two high schools. A third high school is under construction and scheduled to open for the 2013-14 school year. The district is expanding South Middle School, adding 20 new classrooms by August 2012.

The realigned attendance assignments are designed to take advantage of the new school configuration, so that all students from three elementary schools go to the same middle school, and all students from that middle school go to the same high school, said district spokesman Matthew Deichmann.

To accomplish that, a committee made up of district parents devised a new attendance assignment plan for the 2012-13 school year. The plan would require Board of Education approval.

All current fifth-graders at Boone Trail, Duello and Green Tree elementary schools would attend South Middle School. All current fifth-graders at Crossroads, Prairie View and Discovery Ridge elementary schools would attend Frontier Middle School.

Current sixth- and seventh-graders at Frontier Middle School who live in the Duello or Green Tree elementary school attendance areas would attend South Middle School in 2012-13.

Current sixth- and seventh-graders attending South Middle School who live in the Prairie View and Discovery Ridge elementary attendance areas would attend Frontier Middle School.

Current eighth-graders at Frontier Middle School would attend whichever high school they had already been assigned.

The 2012-13 eighth-grade class at Frontier Middle School would become the freshman class of the district's new high school when it opens in the fall of 2013. Students already in high school would not be asked to change schools.

The district has scheduled three open-house meetings to answer questions and receive feedback about the new school assignments, which the Board of Education would probably consider in early 2012. The meetings will not include formal presentations, but district administrators will be available to answer questions and explain the process.

The first open house is scheduled for 7 p.m. Dec. 8 in the Holt High School cafeteria, to discuss attendance assignments affecting Wentzville Middle School and Heritage, Lakeview and Peine Ridge elementary schools.

The second is scheduled for 7 p.m. Dec. 12 in the Timberland High School commons, to discuss attendance assignments for South Middle School and Boone Trail, Duello and Green Tree elementary schools.

The third is scheduled for 7 p.m. Dec. 14 in the Frontier Middle School cafeteria, to discuss attendance assignments for Frontier Middle and Prairie View, Discovery Ridge and Crossroads elementary schools.