I currently have DTV HD DVR receiver model #HR20 which uses remote model #RC64R. On the same TV, I have an older Hughes HD DVR receiver. (Two DVRs on one TV). The Hughes unit is beginning to wear out (bad audio drops - tried several optical cables, same issue - drops). I would like to add another HD DVR to my system. With Directv manufacturing their own boxes now, I would be looking at model #HR22. From the picture, it looks like it uses the same remote. With both of these units on the same TV and in the same rack, this could pose a problem remote wise.
Is there any solution to separate the two (remote control signal)?

I do use a univeral remote for all of my electronics and lighting: MX-500 by Univeral Remote Control.

Thanks

You can set them to 2 different IR codes (actually I think a new firmware now allows 8 different code sets now). Then you can just use the slider switch at the top of the standard remote to choose to send the IR codes to DVR 1 or 2. I am not familiar with the MX-500 but I would be very surprised if you can't do something similar with that remote.

The MX-500 doesn't have the codesets for the DirecTV HD DVRs so if you want to use it to control both units independently you'll have to set them to two different codesets as Murray suggested and then learn all the functions of each to two different device buttons on the MX-500.

I did this with two DirecTiVos and despite being a bit tedious to set up, it wasn't too painful and works well.