Not really.
Let's assume there is one entity with 99% of the hashing power and there are a million entities owning the remaining 1% of the hashing power.
The remaining 1% could always decide to ignore the big 99% entity and fork the chain. The 1% would end up owning 100% of the hashing power again.
Until the 99% entity joins the club again of course.
Now I think of it, could it be possible for the 1% to block the 99% entity?
You're wrong.
http://learncryptography.com/51-attack/. It has nothing to with the the # of "entities", but the percentage of hash controlled. If one entity owned 99% of the hashing power, then they would be able to do a 51% attack at will, and the 1% will have no say. Same for if someone owned 51% of the hashpower, those that own the other 49% will have no say.
"What is often considered a very large flaw in the design of Bitcoin is that hypothetically, if a single entity contributed the majority of the networks mining hashrate, they would have full control of the network and would be able to manipulate the public ledger (blockchain) at will."