simple (?) midi 2 audio trigger

hello folks,

i'm very new to the arduino and haven't managed much more than some smaller midi-related projects in the past. i'm sorry for not posting any code yet as i'd love to have some/any input prior to starting the following project:

for an old simmons sds-8 drum-machine which uses 5 audio-inputs (via jack from e.g. drum-pads / piezos – the inputs are marked "bass-pad", "snare-pad" and so on, as on this picture) in order to trigger its individual drum-sounds, i'd like to build a small box that receives midi-notes and outputs an audio-signal at a designated pin.

i suppose i'd need only 5 pins, each assigned to a certain midi-note in order to e.g. have a C-note output a signal to the first pin -> jack, a D-note output a signal to the seconds pin -> jack and so on.

can anybody give me a hint on how to start this? or any input on the feasibility of this project? i recall having some difficulties with arduino and polyphony in the past (and suppose i'd need polyphony, as obviously multiple pins should be able to output a signal if multiple notes are received at the same time).

sorry for the layman's explanation :confused: .
i'd be gracious for any help!

have got any succes on this project? i need a stuff like this for old analog drum machine. have you got to do it?