Don,
I think what you're asking for is almost completely doable already. Give this a try.
Right next to the "Current Preset" is a little piece of paper witha pencil in it. This toggles the "preset management window". Click it.
Notice in here that you can filter all the ones you want and create your own lists. I have my own personal list under "My presets". All you have to do is "unhighlight (deselect)" all the other ones and place the ones you want into your own "My Presets". Highlight it and close the window (hit the back button on the bottom right corner). Now the only ones you can select back in the Main Pianoteq window are the ones you personally selected.
I live by this setting because now I am going to learn to be able to change presets via midi commands. What a godsend this is.
Hope that helps.
Maestro2be