Invalidating all portlet sessions

Hi!

I have created a simple custom portal based on pluto-portal. From a servlet in my custom portal I 
want to invalidate all related sessions in my deployed portlet applications, is there an easy way to 
do this, using the portal-driver?

I suppose one possibility would be to iterate through all configured portlets and trigger an 
ActionRequest and in each of the portlets make sure that they respond to that request by 
invalidating the session. But I would just want to know if there's a better/easier way?

All portlets are separate web applications.

Regards
Anders