P Code Basefile edit

Hello, long time lurker , first post. I am learning my way around FreePBX and it has been great. I do have one issue that looks like it requires modification of the basefile for Sangoma S series phones. I need to edit P code 23406. I see the basefile edit option in the EPM menu, however, I do not find the P23406 and it does not come up in the dropdown when trying to add it (P23400 and P23401 , but not P23406.

The root issue is that while a call is in the parking lot and an incoming call rings, the incoming call "conferences" into the parked call and the call is released from the phone IF the user presses the BLF for the parked call while the incoming call is ringing.

If there is another solution for the issue, I'll be happy to use it. I basically need to ensure that parked calls/incoming calls can never hear each other and can only interact with the staff/phone users if that makes sense.

Thank You in advance!