Lock minimap, enlarge portion of minimap to entire minimap

[IronForge]

Hi, I'm having trouble finding the trigger to enlarge a portion (topleft quarter) of the minimap (playable area for my map) to fit the entire mini map.
That is because I'm having several game modes, each with different maps, and I have divided my map into 4 quardrants to accomodate that.
So, I want to know how to have Pyramid Escape/Uther Party style minimap switching.

Thanks.