You have to do it twice. After you get the Walgreens/CVS number, click on select pharmacies at the top and change to Walmart and Kroger.
Ahh, so THAT's the trick.
I rarely run Walmart. Get too many folks who REFUSE to step inside Wally World. CVS and Walgreens come up quite often as "faves". RiteAid too. Had some to switch from their current drug store to RiteAid because of the savings.