Modelling Data Hierarchy with SysML

[quarter]

I'm developing a set of Activity Diagrams (object flow) to describe a system where many of the sub-activities generate portions of full data set, analogous to a book with chapters.  Some activities work with individual chapters, others work at the book level.  My thought was to create a datastore hierarchy with a the book-level being the top-level datastore, and each chapter being it's own datastore at the second level.  I created a package for them, and was thinking I could use a bdd to describe a hierarchy using Part Association connections.  But when I try attach the elements, I only see control flow connections.  Is this possible in EA, or is there a better approach to it?   Also, I've looked at using control nodes (merge, join, fork), but I think it would make spaghetti. 

[Nizam]

You can achieve this using nesting relationship,  however my vote will be to create the package hierarchy,  which will align well with your specs

[KP]

was thinking I could use a bdd to describe a hierarchy using Part Association connections.  But when I try attach the elements, I only see control flow connections.

Compositions are certainly legal between SysML activities. If they aren't available from the Quicklinker or the Activity diagram Toolbox, grab them from some other Toolbox (e.g. Block diagram).

[quarter]

OK, thanks.  I'll try both.