Display relationships of search results in Advanced Search

This has come up often on the forums, where we want to display the "relationship details" of the matching contacts. For e.g.

We want to display parent details of all kids in second grade

so basically the foll is used:

• find all the contacts that match the search criteria

• find all the contacts that have the specified relationship type with the above set of contacts

so the "search criteria" does not apply to the related contacts