A user equipment (UE) initiates a positioning session based on ranging in a distributed system of UEs. The positioning session includes a plurality of anchor UEs with known positions that provide information including ranging information and their positions to the initiator UE in post-ranging messages. The initiator UE identifies anchor UEs that provide information that does not significantly contribute to the final position estimate for the initiator UE. The initiator UE, for example, may generate position estimates and associated accuracy levels for different subsets of anchor UEs and may use the accuracy levels to identify a subset of anchor UEs that may be used for positioning in place of the full set of anchor UEs without a significant loss of accuracy. Selected UEs are excluded from providing post-ranging messages in subsequent positioning sessions to reduce signaling overhead and improve efficiency.