Here is the solution for this scenario.

• The main panel will have a talk key to fixed group . the receiving panels will see incoming call just from the main talking panel and the talking panels name appear in their reply key. 

• in this case you do not put a talk key to the fixed group on the receiving panels display. 

There are couple of options if you don't want the receiving panels to see the name of the talking panel appear in the reply key.

1. Using fixed group - but for the main talking panel you set  Prevent Reply signalization option ON for the main talking panel 

The downside of this is that ANY other panel this main talking panel talks to will not see its name appear in reply key.

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2. Using Partyline add the receiving panels into the Partyline as fixed LISTEN only members

place a talk key on the main talking panel to the Partyline

by placing the panels as LISTEN only members to the Partyline, they will be forced to hear the incoming audio on the Partyline , whenever someone talks into the Partyline

but on the receiving panel display they will not see the name of the main talker appear on their display nor in the reply key, they will just hear the incoming audio.

• if you want the receiving panels to have the ability to adjust the volume of the  Partyline , then place a listen key on their panel so they can adjust the Crosspoint level of the Partyline.