Enable P2P video between Polycom VVX and CCX series phones

My company has about 2,500 Polycom VVX 601 phones, all equipped with a Polycom video camera for P2P video calls.

Polycom is no longer making the VVX series phones, so we're unable to get new phones for new employees, or replacements for broken phones, so we're starting to purchase CCX series phones.

Currently, you cannot make a video call between a VVX and a CCX phone. You can make VVX to VVX video calls, and CCX to CCX video calls, but you cannot make a video call between the two series.

This lack of interoperability is hurting the value of the phone system and impairing our preferred method of communication between internal employees.