Something that is a little annoying for me is that this panel has only two radios. When you choose com or nav in either the lower EICAS window or the Throttle window the other radio in the other window changes to the same thing. Thus you are stuck with only two radios. To remedy this I installed the radio stack from the default 737 panel. If you have one radio tuned to the VOR and one tuned to ILS you have no communication with the tower. Until I installed the 737 radio stack this was extermely irritating. I would like to make the radios all independent from each other but how would I do that?

The fact that you reached your desired result by installing a different gauge proves it can be done.

I'm not familiar with this panel but it sounds like both gauge sets are using the same gauge.  The solution may be as simple as copying and renaming the gauge (radio2.gau) and changing the panel.cfg entry accordingly.

The panel in question is the Ken Mitchell A330 panel on page 16 of the FS 2004 panel section.