Automatically refresh page

Hi. How can I reprocess a page if a certain variable is received. I am selecting companies for specific users from which they can select the required company and proceed further. Using variables on the same page using PHP_SELF. This then shows a list of contacts for the chosen company. In some cases the user only has access to one company. I would like to have the page skip the company choosing section and proceed straight to the list. I had thought to do a count on the rows returned from the database and if that was == 1 then assign the relative variable and refresh the page. Is there perhaps an easier or better way to achieve the same results? Thanks Kevin