Hi Shikamaru,
I think this is the setting you are referring to;
Ad Hoc Conference Settings
Cisco CallManager Administration provides the clusterwide service parameter, Drop Ad Hoc Conference, so you can choose when to drop an ad hoc conference on the basis of the value that is entered in the Service Parameters Configuration window of Cisco CallManager Administration.
To configure the value of the service parameter, perform the following procedure:
Procedure
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Step 1 From Cisco CallManager Administration, choose Service > Service Parameter.
Step 2 From the Server drop-down list box, choose a server in the cluster.
Step 3 From the Service drop-down list box, choose Cisco CallManager.
Step 4 From the Drop Ad Hoc Conference drop-down list box, choose one of the following options:
Never - The conference is not dropped. (This is the default option.)
When No OnNet Parties Remain in the Conference - The system drops the active conference when the last on-network party in the conference hangs up or drops out of the conference. Cisco CallManager releases all resources that are assigned to the conference.
When Conference Creator Drops Out - The active conference terminates when the primary controller (conference creator) hangs up. Cisco CallManager releases all resources that are assigned to the conference.
From this good doc;
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a00803edae2.html#wp1044647
Hope this helps!
Rob
