Mouse button query for trackball/spinner

[LeedsFan]

Sorry if this has been asked before, but I can't find anything so far....

Basically, I'm pretty tight for space on my two player control panel. Each player has 7 button in Neo-Geo style layout with trackball and spinner in the middle (with spinner just above trackball).   OK.... I think you can picture this now.  My problem as such, is that I don't have room to get two buttons in for the tb/spinner to act as mouse buttons.

Can I use the first two buttons on the player 2 side? I'm using the J-Pac and Opti-Pac for the installation. Obviously, I need the Opti-Pac for the actual cursor to move in the games. But the J-Pac will automatically use the first 3 (or 4) buttons from the existing cabinet loom. Can I also wire these first two buttons into the Opti-Pac to act as mouse buttons?
Or maybe buttons 5 & 6 if it conflicts with the J-Pac?

The way I see it, is that games in Mame are going to be configured for either mouse or joystick.... not both. If I can do this then my panel will also look neater as well. But I'm not 100% sure about this......  

[daywane]

I do not have the same set up as you.
but If I were you , I would drop the wires from 2 of your buttons and replace with the leads from the mouse.
all buttons being read from Ipac except 2. the other 2 hacked into the mouse.
but like I said I do not have mine ste up like yours.
all mine are game pad hacks and my track ball is usb and has its own buttons. My spiner is going into another cab. I will be going with joy/to mouse program on that arcade since my spinner dont even have buttons