A carefully worded title can quickly inform individuals whether that item is likely to be important to them. One of the problems of email is that it is not always as reliable as may be hoped. Writers often assume that because a mail has been sent that it has been received - and read. This may not be the case, for a number of reasons. This is one reason why it can be a good idea to ensure that all mail broadcast to the group is archived on the central site.
Any partner missing out on a thread of the correspondence can then consult the archive.
An alternative or supplementary means of communication is the newsgroup. Management Ideally one individual at the central site should be in charge of managing the data held there. Each project will evolve its own directory structures. The Data Manager and other project members should have different levels of access to the files. Only the manager should have write access to all the files, other members should have only read access to most files.