We have something similar at Pennycomequick roundabout in Plymouth. Googlemaps will show it very clearly.

In our case there is a crossing on a sideroad (Stuart Rd) across the approach to a small RBT, where a lot of exiting (ratrunning) traffic can hold up the main road (Alma Rd) approach from their left. We have call/cancel loops on the main road, and when the queue reaches them they insert a demand for the peds across the sideroad.

The sideroad onto the RBT has a central island with a Zebra across it, so traffic exiting the RBT isn’t held up by the signals.