Macro value "Text" linking to input cell value of another sheet

[guatelize]

Hello
Based on my previous thread :

http://www.vbaexpress.com/forum/show...ight=hide+rows

Is it possible to link the macro value from a cell from another sheet, so the user can choose his own letter to hide/unhide the rows :

Value "O" to sheet 2 range B2:
 If UCase(Target.Value) = "O" Then 
    Value "C" to sheet 2 range B3:
ElseIf UCase(Target.Value) = "C" Then 
   'As well for the module : 
   (UCase(cll.Value) = "O" Or UCase(cll.Value) = "C")

Thanks very much for your help