UI technology for segmentation and consolidation (portal alternative)

Question

I'm looking for a preferably Java-based technology that is able to:

• Separate development tasks between developers and does not requires them to access all the UI for development and testing. I'd like to create separate groups who develop the UI on their own.
• Consolidate the end results as a coherent application.

Yeah, I know, this is what portals and portlet containers are for, however I'm looking for alternative technology solutions - if there is any.

For example I can think of the followings:

• Spring MVC with clear separations on the scopes and "clever" merge process
• Struts actions and pages with clear separations on the scopes and merge of the configuration

Update: I haven't specified a few more requirements, but I need SEO, friendly urls, and do not consider Wicket (because it is hard to find developers) and JSF (because it has limitations I do not like).

Answer 1

I've concluded that our way would be SpringMVC-based, further discussion might continue at Spring forum