It shouldn't affect the other heads, since they aren't connected in branching species. The only thing that would is if it happened to be a contagious infection. Not terribly much that can be done to stop it if it does. Can you give a summary of test results? Also, what do you want your thread title changed to?
Wait...it's not all connected? So, when one head eats, the whole unit (animal) doesn't get food? Each head has to eat separately? I'm asking because I gave two of the heads krill today...also when the two heads were eating, all the rest closed up fully. Odd creature I must say.