Disclosed are techniques for wireless communication. In an aspect, a position estimation entity configures a sidelink anchor group with sidelink anchor(s), to which respective sidelink PRS pre-configuration(s) are sent. A UE transmits a request to schedule an on-demand sidelink PRS position estimation session of the UE. The position estimation entity provides the UE with assistance data associated with the sidelink anchor group for the on-demand sidelink PRS position estimation session. The UE sends the sidelink anchor group a sidelink PRS trigger to perform a sidelink PRS exchange with some or all of the sidelink anchor group in accordance with the respective sidelink PRS pre-configuration(s).