Keybinding help

Hello.  I'm wondering if anyone knows how to use the same keybinds for more than one level of spell?  For example, if I keybind ® to a level 1 spell, when I go to bind a similar type level 2 spell using ®, it removes the keybind from the level 1 spell.  I would like to keep the same keybind throughout the various level spells, but it seems the game only allows one set of active keybind at a time.

This would save a lot of time during combat moving from level to level without having to refamiliarize myself with all the spells again.  I have a specific keybinding scheme carrying over from various mmos.  I would use (Q) for all debuff, (W) for all cc., (A) for all self-buff, ® for all attacks..etc  But, everytime I keybind a higher level spell to a key, the game would remove that previous keybind that I use for the lower level.