Models sharing core entities

I am planning to use ArgoUMl with AmdroMDA to generate as much of a 
Jetspeed Portal as possible.

One of the issues that I think will come up in using Jetspeed is the 
need/ability to break down a fairly big application into a set of 
JSR-168 portlets.
This implies, I think, that I am going to have a number of AndroMDA 
projects in ArgoUML ; one for each Portlet since each Portlet is an 
independent object that is loaded into the Jetspeed Portal depending on 
the user profile, etc.

I think that this is going to result in the same basic entities 
(employee, business unit, code tables, etc.) appearing in many ArgoUML 
models.

It seems to make sense to define and maintain these entities in one 
place and import them  into each model in much the same way that the 
basic AndroMDA entities are incorporated into the model at the start of 
a AndroMDA project.

Is there some way to do this, using ArgoUML, so that changes to the core 
entities can be easily replicated to all of the portlet models without 
having to go to each model and manually change each class in the core 
that has changed. The work is one issue; the probability of forgetting 
to make a change or making an error in making the changes in one portlet 
model is pretty high and will be hard to find when different portlets 
handle the same entity differently.

Suggestions about how the core entities should be organized to make 
portlet modelling easier would be appreciated.

Ideally I think that I would like to be able to export part (or all) of 
a master model of classes and import them into other models overwriting 
any existing instances of the same entity.