You may want to take a look at some of the new features at the PSR-Tutorial site. You can make your own Multi-Pads using Michael Bedesem's new program, which can be found at http://www.psrtutorial.com/MB/padmaker.html This would allow you to create a multi-pad that does exactly what you wish and incorporate it into your song(s). Additionally, you'll find links to thousands of new Multi-Pads, some of which may be what you are looking for.

Good Luck,

Gary