In such special cases you would have to have special rules set up.
Now I think we are starting to get in trouble. Who gets to decide which monopolies are favored and allowed to survive and which are broken up? How is it decided? If it is the government, the decisions will in most cases be political. Is that a good way to run a society?
No trouble; manufacturing is one thing, distribution is another. Manufacturers would not have their own distribution centers.