You can easily do this with ApplyMap.
First, you must store your division names together with division numbers. I have done this in an inline in the script, but you can use any source - a DB or an Excel sheet. Then all you need to do is to construct what you want with ApplyMap():
Mapping Load * Inline
DivisionNo & ' - ' & ApplyMap('NameMap',DivisionNo,'Unknown') as Division
From Source (...)