They can be bridged, but usualy at a "D" check input. Several VIP operated aircraft are on the Boeing LUMP Programme, using MSG3 This puts the "C" checks at 24 month. Aircraft are VP-B or VP-C registered. An example:
Boeing 727 aircraft: 1971 Boeing 727 for sale on the Aircraft Exchange
MAINTENANCE PROGRAM:
The aircraft has a full Boeing CPCP program defined in the Maintenance Schedule and is fully compliant. The aircraft has been operating under the standard Boeing Low Utilization program and has been transitioned to the new MSG-3 Boeing Low Utilization program under which the C checks are performed at 24 month intervals.