Limiting Connections?

Ok so basically, I want to be able to host a tone of files, but they will be under intentse streign from connections, were talking tons of people downloading at the same time.

Is there a way (using PHP or something) that will allow me to limit the amount of users downloading a file at the same time. Perhaps with a username / password login system?

So like only 10 people can download a file at once?

Thx dudes