OK, so you have 4 results pages with the search form:
searchall.php
searchcategory.php
searchline.php
searchrep.php
On each of the pages, in the DataAssist search behavior, create a KeyWord search that uses the desired column.
For example on the searchline page page, set the Key Word search to use the Clothing line column.
On the searchcategory page, set the key word search to use the category column.