If were just throwing out concept ideas here, yes a database would be great to do that type of cross referencing...The cool thing about doing somthing like this you could easily make an interface like a search engine that is almost like a frontend to the database...somthing where you could do simple sql queries like "select hostnames,urls from database-name where hostname like .de sort by urls". Somthing like that could easily be put into a frontend cgi script that had a bunch of drop downs and stuff...The only complexity to this is deciding how you want to sort your tables. The acctual frontend is simple dbi stuff.

or at least in my humble opinion of course