How to design a file container in C++?

My plan is to build a fileContainer that consists mainly of a std::map that associate specific files to an ID. Each file has for attributes a ofstream, a path (string) and a few other information.

The problem is that an ofstream cannot be copied (Why copying stringstream is not allowed?) and cannot even be moved (Why can't std::ostream be moved?). One can therefore not create file objects to then insert them into the map of the fileContainer.

What I am trying to do is something like

file f(arguments...); // create a `file`
FC.insert(f);         // Note the FC is a global singleton of class `fileContainer`
...
{
   file& f = FC.getFile(fileID); // find a specific file in the file container
   f.open();
   f.write(s1);
   f.write(s2);
   f.write(s3);
   f.close();
}

I fail to see how such functionality could be achieved without having to copy or move a stream. Can you help me out to build this type of functionality?