A drum kit can to have 73 Waveforms, but only one per Key, C0 through C6.
A Waveform can have 256 Keybanks.
A KEYBANK can contain two samples (to accommodate a stereo sample or a left mono/right mono pair) and a Keybank is defined by a Note and Velocity Range.
So in theory each velocity 1-127 could be (at maximum) a different stereo sample.

Therefore a snare drum Key can contain 1 Waveform, but that one Waveform can be organizing many, many samples. As many as 256.

You wouldn't do that with drums because the samples responding at a velocity of 1 (would hardly be used), and the difference between it and the samples at velocity of 2 would hardly be appreciated. You will find most of snares and hihats in Montage have 3, 4, or 5 switches due to velocity, this is a more practical and a better use of the architecture. Just because you could have a different sample at each velocity, 1 thru 127 doesn't make it a good idea. 🙂

Multiple samples can be imported to a Key, you differentiate them by stacking them vertically, that is, setting the Keybank's Velocity Ranges so that no more than two mono (or one stereo) samples occupy the same ranges.

Waveform creation ...
When you add a NEW WAVEFORM within a Montage Drum Kit (see diagram on page 126 of the Reference Manual), the first sample is imported directly to the selected Drum Key, as Keybank 1
If you wish to create a vertical stack for velocity triggering, you would touch the ADD KEYBANK box, then load the next sample to Keybank 2 (same selected Key), and so on. You can set a unique Velocity Range for each Keybank you add... thus creating the velocity switch points.

You can construct such velocity drums in the Montage, however, your samples must be trimmed (edited) and ready to go. The Montage is not a sampler and therefore cannot further edit your sample data. Just FYI.