Let us know if the P-FET idea works.

BTW
Be sure to evaluate if the extra components needed to load switch the regulator cost more than a regulator with a shutdown pin.....you know the issue that happens so often.....spend $3.75 each for 40,000 of a part on order to use what you already have 40,000 of when the alternate part may be just $3.10.

Michael Karas