I would like to find out how a group of people can work on a single model.

Example:
A creature model is built and 10 blend shapes have been established for facial animation. The model is not painted nor rigged nor have the blend shapes been remodeled for the various expressions.

The question is; how can you assign 1 person to paint the model and another to rig it and another to model the blend shapes, all working simultaneously at their own workstations then, in the end, have all of their work applied to a single copy of the model file so that it has the paint and rigging and remodeled blend shapes? Is it a network thing like when a group of people can all modify a single Excel spreadsheet and it will update with each person's input or is there a way to bring nodes from other files (.ma or .mb) into a "master" file.