Scenario: User needs to listen to several different groups of Partylines. Only one group can have listen active at a time. Talk keys must be individual.
1. In panel programming, set up a stacked key for each group of Partyline listen keys (see solution #00003112 - How do I stack keys in ECS or EHX for IFBs or other combined ports?)
2. Create an interlock group including all of the stacked keys (see solution #00000668 - What is the function of key panel "Interlock Groups"?)
3. Set up individual talk keys for each Partyline.
4. If necessary, individual listen keys for Partylines can be added to the interlock group to act as solo listen keys.