StringMid would be an option >>
Local $sHostName = "LKIQRTI01"
Local $sLetter = StringMid($sHostName, 4, 1)
Switch $sLetter
Case "P"
ConsoleWrite("P was found." & @LF)
Case "D"
ConsoleWrite("D was found." & @LF)
Case "Q"
ConsoleWrite("Q was found." & @LF)
Case Else
ConsoleWrite($sLetter & " was found, which is the rest of the alphabet." & @LF)
EndSwitch