First you will need to know the Map ID of the area(s).
One way to find them is using "/litemount location" when you are in that location, or "/litemount maps text" to search all areas for the given text.
- Create a flag to group the mounts you want, and flag them with it.
- Add a line like this to the top of the action list for the key binding you are using:
where MapID is the numeric ID of the map. You can separate multiple areas with slash (/).
Most maps in WoW are in a hierarchy, and the [map] condition will match anywhere in the entire path to your current map. So you can, for example, put in the ID for an entire continent.