This paper proposes a new application framework for group tour guiding services based on RFIDs and wireless sensor network. We consider a sensing field mixed with multiple independent tourist groups, each with a leader and several members. Members of a group will follow the moving path of their leader, but may occasionally roam around randomly based on their interest. Sensor nodes have to track leaders' locations and maintain following paths from members to leaders. A member may ask where his/her leader is, and a leader may "recall" his/her members. We propose a feasible solution to such an application by using existing technologies. A group guiding protocol is presented. The design enables reliable group guiding at low cost and low traffic load.