Garmin: Maps order based on their scale

Hello there,

Can anyone please explain how does the display order of multiple maps in a handheld works?

What I mean is for example if you have a City Navigator NT and you zoom out to a certain scale, the basemap will take over and you no longer see the city navigator. but for example, if you have OSM map loaded instead of the City Navigator NT, it will switch to basemap at higher scale.

is there a place to set the preferred order of maps or manipulate at what scale those switches happen?

Thanks, Tariq