Title is self explanatory :)

Ideally, you could just put check marks next to the dungeon(s) you're looking for. This would be useful, if you're searching for a M+ key of a certain level for several dungeons at once.

It is possible to filter by multiple dungeons using keywords (see list of all keywords). Please have a look at the first two FAQ entries why I am currently not planning to add checkboxes for dungeons.