I have seen that some pads use the dual trigger for the rimshot, and if you never play on the rim of your toms, you might as well add another trigger, you could even build your own simple trigger for something like a cowbell https://lemmy.world/post/30587588.

Dual trigger inputs use a stereo jack, where the two internal triggers are on tip and ring (with comon ground), so to make a split cable, you just solder the individual trigger-wires to two mono jacks, like this:

You can also buy premade splitter cables, but wheres the fun in that :-)