multiple gmaps
 

Is there a way to set the big map and mini map to contain multiple gmaps?

not with two separate gmap files, but you can pretty easily combine them into the same .gmap with just copy & paste (open both gmap files in text editor)

if you wanted to get technical, you could combine two gmaps with some parsing script, but it's getting pretty complicated and wouldn't work in some situations (depending on what you need to do it for). It would involve editing the .gmap files with a text parsing script to make it one gmap file.

well, we're having 2-3 different gmaps for a world, and I wanted to be able to show them at the least on the minimap. They need to be seperate if at all possible.

They can't be separate. Make a custom map and just display it when users press the map key.