The Zapier module likely sends the same webhook payload for every new payment, so Zapier has no "which user to notify" info unless the payload includes it. Check the webhook payload in Zapier's trigger step: if Perfex sends an "assigned" or "responsible" user ID (or staff id), add a Zapier Filter step so the push notification only runs when that field matches the user(s) you want. If the payload doesn't include user info, you’d need to either (a) see if the Zapier module has an option to include "assigned staff" in the trigger data, or (b) use a lookup (e.g. get invoice/lead by ID and check assigned user) before sending the notification.
If you ever want to move this logic to n8n (more control over filters and no per-task Zapier cost), there’s an n8n bridge for Perfex that adds HMAC-secured webhooks and bi-directional sync – you can build the same “payment → notify only user X” flow there. One-time purchase: https://soluradev.gumroad.com/l/perfex-n8n-bridge
