You can set the ’level’ in menus. By default it goes through all levels. (level = 0)
If you set it to 1, it will only show a menu of parents.
If you set it to 2, it will show the parents and their direct children.
Set to 3, it will show parents, their children and the children of the children, etc.
Example:
[!Wayfinder?startId=`0` &level=`1` !]