Generally GenericContent based modules have metakey Category which is set in the web.config. Category metakey has property searchable="True
" which means that all items that has been categorized are searchable.
You could try to create a collection of categories and add them to a drop down then concatenate the text you have entered in the searchbox to the value of the dropdown. A good sample of this approach is our Forum search
If your approach is different, let us know.
the Telerik team