Got it.
You need to go to analog processing, select the sample you want to cut itself off as the low and high, then go to Keyboard mode with the data slider (number 21 on my OS), you want solo set to on, leave nontranspose off. Now it is essentially in mono mode. Be careful since any and all samples you select in analog processing will effectively become monophonic, so If you select the whole range of pads, you will only be able to play one note, since any other sample will cut off the rest. So it can take you down to one note polyphony. But you can do this with one note or a group of notes, say kick snare by hitting change voice in analog processing and defining a new range of samples, so if you got them spread on the pads chromatically, you can have the lowest two cut each other off, while the rest ring out and don't cut themselves off. This in use with the release and sustain levels set high will give you a one shot / mono effect, which seems to be what you are after.
Man, the emax really has it, I thought for a while it couldn't be done, but there it is and it's very flexible, although peculiar in implementation.