Hi mark4man.
Yes the SRX boards are made up of the wave forms from several SR-JV90 boards. For example. I did own the SRX-07. Here's a cut from the Planet-Grooves website

The SRX-07 Ultimate Keys Wave Expansion Board offers a massive collection of keyboard sounds and loops. This 64MB card contains all the waveforms from Roland’s popular SR-JV80-04 “Vintage Synth,” SR-JV80-08 “Keyboards of the ‘60s & ‘70s” and SR-JV80-10 “Bass & Drums,” plus selected waves from SR-JV80-09 “Session” and SR-JV80-03 “Piano.” With approximately 300 all-new Patches and 10 Rhythm Sets, the SRX-07 covers all the bases including some tasty loops.

There may be patch listing or waveform listing somewhere on the web so you can see if the exact drum waveform your looking for is on the SRX-07 board. I've heard pretty good reviews on the SR-JV80-10 Bass and Drums, which would mean the SRX-07 would have those sounds.

I bought mine SRX-07 from kraftmusic.com. I had to wait until they had it in stock. The wait was about 2 weeks. And they had the best price I could find, about 200 bucks. Which can be cheaper than buying 3 SR-JV-80 boards used on ebay.

Best wishes dude.
Bob
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