I have been approached by a group of 8 companies to provide for them an information exchange portal. Here they would store files, documents and posts, organized by category and sub category, and a bulletin board with latest news and events posted by the users.
The companies indicated that SharePoint wont’t work because the each have their own domain, and they need this solution to be independent from any of them. They also want to restrict each company to 3 users, and if another company wants to join, the admin of 3 other companies need to approve.
My question is - would this be a development project (I'm a PHP developer); or a sourcing project, where there is something pre-made that can be adjusted? What would a bull park cost be for this?