Hi Martin, Thanks for your advice. Having had a chance to think it over I prefer the "configurable" way. It is a bit more work, although not that much. My plan is to add an extra column (source) in the Map table behind the http-link column so this should not have any influence on other routines using the Map table (I'll test it first :) ). My idea is to allow any Perl expression to be entered in the "source" column. This could then be a source field the user enters, a call to some routine or whatever one can think of. I am not sure what you mean by a "normal" user but I would expect someone to even think about configuring the back-end would at least have some knowledge about database techniques, scripting languages like Perl, etc. Anyway, when I get it to work I will post it and add some documentation as well. Kind regards, Tom Hesp