That's not a problem with those Leaflet plugins! Your users won't even notice the absense. See this map for a demo.
Does not allow selecting zoom levels that are not in a predefined list.
Include the js file and add zooms: [1, 5, 8, 14] option to your L.Map object,
with zooms of your choosing.
Allows restricting L.TileLayer zoom levels to a predefined list, while
not limiting map zooming functionality. Missing levels are interpolated from
previous, or a minimal existing zoom level. Be careful: set minZoom option
to the minimal native zoom, or number of tile request would be enormous.
To use, include the js file and add nativeZooms: [2,5,8] option to a L.TileLayer
object, with zooms you have.
Those plugins were written by Ilya Zverev and published under WTFPL license.