One Way Conference with External Call

Hi i have Scenario ,

Where 20-30 of Extensions need to listen 1 external sip call , dialed by 1 extension , Just Listen Not to Speak or interact.
the listening extensions must be muted .

Currently i am giving everyone ChanSpy access it works but as no call logs or they can also listen other calls to.

so is there and Neat and Clean way to do it, give just hint and will try to start work on it

Thanks , its my first topic in this forum , Any help appreciated.

i was hopping to get some head start.

Read this:

Head start maybe at:-

look at the options -o and -e(123:125:127) and a couple of examples to get you going