Well, I don't have a siamese, but, I do have a chronic tuxedo vomiter....as long as the vet gives the ok, I make the following suggestions:

1) incorporate hairball gook into the diet...I forget what it is called, but, it is that corn syrupy stuff;


2) when feeding wet food, do it in small increments;

3) if you have scarfers...make sure they don't go long without food...cause then they gobble it up, and...vomit it up!