I have an idea! : )
Make some thin gel cups out of sodium alginate.
Put a gel cup inside your cylindrical glass then fill with the alcohol that you want. Then put a cup on top of that and fill that gel cup with a different alcohol. And then one on top of that and so on...
Then serve it with a straw so the straw can pierce through the gel cups and you can get to the layers that you want.
I think you can even flavor the gel cups with different flavors if you want to be fancy!