As a crude workaround, you could functionally accomplish this with CFNA to a second line appearance, where the first line appearance is set to ring on some but only flash on others, then rollover on no-answer to the 2nd line which could be immediate-ring on all sets.
Unfortunately one of the several feature gaps between Mitel & Cisco is Cisco does not support the delay ring feature.
Original MUG/NAMU Charter Member