Some hydraulic modelling software allows users to specify a remote node which as the target for PRV pressure settings. For example a PRV at the entrance of a zone might modulate so that the pressure doesn't exceed 30m at the node in the zone with the highest elevation.

Any chance this could be added to WaterGEMS?

Here is some research about adding a similar feature to EPANET: https://iwaponline.com/jh/article/24/3/642/87798/Smart-pressure-management-extension-for-EPANET