2 controllers, 2 vstis simultaeneously?

Hi, I have a drumpad controller (vestax pad one) and a keyboard controller (akai lpk25).

In preferences-midi, i have the drumpads in slot A and keyboard in slot B.

I want to play two VSTi at the same time (a drum vst on the pads and a vibraphone vst on the keyboard).

So far, I can only get both midi controllers triggering the same vst.

How can I set everything up so that the drumpads only trigger the drum vst and the keyboard only triggers my vibraphone vst?

as seen in the preferences menu, those ABCD slots are Master controllers, as in, they control everything. What you want is to go into the midi settings of your instrument directly and assign the midi input of your controllers separately