Solved using an AHK script.
This script sends "1" to Mala when you press 2, 5, 6 which I have linked to P2 start, and P1coin, P2coin. By using the #IfWinActive, MaLa, call this only runs while the mala window is active, i.e. mame, anything else will run normally without 2, 5, and 6 being remapped.
;This script is to use either coin up button and/or either start button to start a game while in MaLa.
setTitleMatchMode, 2
DetectHiddenWindows,on
#IfWinActive, MaLa
#Persistent
2::1
5::1
6::1
return