Hi Ethan, need help on displaying multiple stores per service (multiple reference help)

I have created 2 collections

1. Service (Flu Vax, Whooping Cough Vax etc). I have added a multiple reference to my second collection titled 'Pharmacies' ie Pharmacy A, B, C have this service

2. Pharmacy list - showcases Pharmacy A B C, their locations, regions and numbers

I want a customer to be able to go to a service page which is a dynamic item page and it's all set up and at the bottom have it filetered by the Service they are visiting. And then have a dropdown option of 'Region'. I can't seem to get Wix to show only the pharmacies that offer only that service. It's still showing all the pharmacies in the group.

Any advice is very much appreciated.