question about flight illusion gauges and pm systems

hi I want to buy 3 gauges for my mip panel and over head apu exhaust gauge,oxygen pressure and flap gauge for mip one thing that is unclear is how many gsa boards I need to work with pm systems I or 2? this is why I as im confused............................A module can be a gauge, an Input/output module or a radio module. For normal operations, 1 Central interface module is enough.
Only when you want to drive the gauges by PMsystems from Project magenta, will you need another Central Interface module. This is due to the fact that each interface needs his own port.let me know please tks.

Have you emailed flight illusion direct? They are pretty good with answering queries.