EXS 24 Logic Sampler Users Group

I'm trying to do something with an existing patch, and I'm not finding it in
the manual anywhere -

I have a patch with 4 groups for each note, with dynamics that go from mp to
f to ff to fff.

I'd like to be able to crossfade between the groups *during* a single note,
using the mod wheel, to simulate a swell. Is this possible?

TIA for any pointers.

 - PH