the wiring loom inside the voyager is not jamma. it uses a standard pc setup with a card plugged into the parallel port for the guns.
there was a shoot'em up game i worked on years ago that used an amiga pc and a video laser disk player (the ones that took the 12 inch laser disks).

the easiest way to convert this system to a mame set up is to install windows on another hard drive and use the windows os selector on boot up. you will then just select the voyager hard drive or the mame hard drive on boot up.
we may have a problem if the voyager commands are set to the C: drive, if this is the case the game may have problems.
if that is the case then we fit another pc into the cabinet and use a selector switch on the output of the both graphics between the monitor input and the card outputs.

or we make up a jamma loom and buy a jamma board and do the same thing with the video outputs.

the mame set up would be the cheaper, easier and the better way to go, as i have noticed with those jamma game boards several differences between the original games and the jamma games.
but the mame versions of the games are spot on compaired to the original games.