Don't Feed the Dogs

Scarlett has a really bad habit of feeding Lady and Nala whatever I give her to eat.  I tell her NO NO feed the dogs.  She cries.  I feel bad and hug her.....then as soon as I turn around she is at it again.  ARG!!  I'm sure she understands me.  I know the dogs understand me.  They run and hide as soon as they see me coming if they are eating Scarletts food.  I don't know what to do.