Sorry there is not, the assiciative database is built in the load script. As long as your field names are the same they will be linked. If your problem is that the original data source is no longer available then you could load the current qvw into a new qvw and then manipulate the tables so they are not linked.
However, there is no reason that you can't show the columns from each table in a table box like you describe, you may need to use the "Omit when Null" setting from the presentation tab in order to suppress items that are on one table only.
