Hi Cliff,
sorry for the confusing question, maybe I'm confused by myself

I should think about my formulations before posting.
Seems that I've not understand the pipes concept completely.
Of course I don't want to separate every function to a core of its own.
The question was regarding the arrangement of modules and if it's a appropriate way to place 'submodules'
inside a 'mainmodule' and if all these modules could talk to each other without involving the shell.
Perhaps the differentiation in 'main-/submodules' is completely rubbish, I should think about it!
But sometimes I tend to think too much about whether the things the 'right' are.
Instead of thinking and asking too much I should just implement my ideas to see if it works and dispel doubts ;-)
You certainly can plumb cores together without them having to be plumbed to the shell. Have a look at this slide in the MultiCore Overview Presentation:
http://puremvc.tv/#P002/T235
Yes, that's it... don't know why I don't registered this slide before.
Now I'll try to install my pipes to get the cores connected;-)
Thanks for help!
Olaf