Play-doh colors are meant to be mixed and combined and integrated. But the very reusable nature of the medium (yes, Play-doh is an art medium) discourages the user from doing so; we don’t worry about mixing paint or clay or sand or whatever because when the art is done, it’s done. Nobody scrapes the watercolors back into the tube.
The pinkish-red hue that’s included (this is a grilling set) is actually pretty spot on for a nice medium/medium-rare center. I doubt these will be easy to separate, but I think that should be ok.