[VoiceOps] Park Button on Polycom Phones

Anyone know how to make an enhanced feature key (EFK) on Polycom VVX phones that lets you park a call on a line you are monitoring. Ideal condition would be to hit the park button on an active call, and then hit the line/blf you want to park the call on. The EFK's I have seen out there want you to manually enter the extension of where you would like to park the call. That is not ideal.