I did something close with my 722 and two DIshPro UHF 6.3 remotes: one on TV1 and one on TV2. I did that because none of the TVs were with the 722 which was in an equipment closet.
21.0 remote set them both to the same address example address #5, set receiver address for TV2 to address #5. Both will control TV2 from any room they are in.