Alphabetic filtering with special characters

hi all,
I have a requirment to filter out all users in the database by starting letter.
so we will be having link buttons for  A B C D E..... Z.
If user clicks on A, all users whose name starts with A is retrieved
Now the concern is, if there are users whose name starts with any special chars how they can be classified under any filters
OR
just copy pasting what the client asked me


In terms of filtering UTF characters, is there no way to set it up so that all 'A' (i.e. Ä, Á etc.) characters are assigned to A (i.e. some way of grouping together in an "if else" kind of rule)?


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