Define a value list of custom value and list your differnt text items in order from Most restrcitive to Least.
Now you can use this value list to specify a sort order.
You can do this on a relatiosnhip between tables in Manage | Database so that you can place fields from the Most Restrictive record on your layout. Double-click the relatiionship line and choose the sort option.
You can do this in a portal so that the Most Restrictive Rows sort to the top. Select Sort in the portal set up dialog.
You can do this with a found set of records to sort most restrictive entries to the top as well. Select Sort from the Records menu.
You use the same "sort" dialog in each case. After selecting the text field containing your restriction text, click the Custom order based on value list option and select your value list.