As far as I am aware the RTP path must go through both systems, especially with H.323, what you are after is more of a SIP function but again I am not sure if the Cisco IOS supports this capability any way, as this would reduce the call control functionality of the system.
However in saying that H.323 is old school and I never played much with it only when doing Tier-1 carrier termination back in the days.
Then again I could be wrong and someone from Cisco will provide the correct answer never done it myself or had a need to do it and not sure what advantages you would get doing this other than preventing multiple paths in the routing of the call.
**When you rate a persons post, you are indicating a thank you or that it helped, but at the same time you are also helping to maintain the community spirit - You don't have to rate posts and you wont be looked down upon :) *
Configure Multicast Paging on the Cisco IP Phone 7800 Series or 8800 Series Multiplatform Phone
The Cisco IP Phone 7800 and 8800 Series Multiplatform Phones provide voice communication over an Internet Protocol (IP) network...
Add Call Park on a Cisco 7800 or 8800 Series Multiplatform Phone Key Expansion Module
Call park allows the user of the phone to put an incoming call on hold so that the call can be retrieved on another phone. A call is park...