A print filter is normally able to work with all printers that accept its output, so you can usually skip this part of the filter definition.
You may, however, have some printers that are or inappropriate for the output that the filter produces. For example, you may want to dedicate one printer for fast turnaround, only sending files that require no filtering to that printer. Other printers of identical type may be used for files that need extensive filtering before they can be printed.