Few things, the "splitter" device on the back of the 722 is the DPP seperator. Diplexers are always used in pairs. If you already have a rg6 cable going to tv2 then yes it is possible to swap the diplexers around to do what you want.
I dont follow exactly what you are trying to acheive with tv2 in your diagram.
thx for the reply, a dpp seperator is going into the sat inputs on the 722 (not a diplexor, my mistake). I have RG6 only. Also, I am trying to mirror the TV2 output onto 2 TVs on 2 different floors hence the whole mess.
Just split the tv2 using a standard splitter like you had and then run it into the diplexor on the vhf/uhf port. Note that the more times you split tv2 the quality goes down. Your UHF remotes may not working if too far away. Let us know if you have more questions.