This option has worked well at congregational prayer times, like a Sunday evening service, or prayer during a congregational meeting.
For a specific topic, have three people pray, with slightly different assignments. Three has a good Trinitarian feel to it!
Some examples:
Pray for the Youth program, asking three people to pray, covering the children, the teachers, the leaders. Or possible the Sunday School, the Youth Group, and Vacation Bible School.
Or pray for a college campus, covering the students, the Faculty, and Evangelistic Groups.
Pray for your church: Thanks for God’s past blessings, For Current Needs, Future mission