Hide membership of a folder from view from visitors?

Hello,

I have been trying to find the answer for this for the longest time, but all my googling has come up short. We share quite a bit of documents with people outside of our company that bid on certain projects, and we would like a way to prevent when one of those people hops into the document folder from them seeing who else has access to it. Currently if they hit the "Details" portion of the folder page they can see every single email address that it is shared out with , and alas, every member of the competition. I know the "easiest" way would be to create separate folders for each bidder, but it could end up with a situation where there would be 80 different folders. Is there a way to create a custom permission where they cant see this info?

Thanks!