Nested Data Regions - Reporting Services

Is it possible to nest list items that use different datasets? I am currently working on a report that consumes information from several different tables. Is there a way to achieve this using nested data regions?

Here are some of the items from the report-

IT Plan
----------
IT Plan Headers 1-10


IT Plan Projects
-------------------
Project Headers


IT Plan Project Sponsors
-------------------------
Sponsors 1-n

IT Plan Project consumers
---------------------------

IT Plan Project Survey

------------------
Survey Qs and Responses...


IT Plan Project Alignments to Intiatives
-----------------------

Alignments 1-n

..... several other such subsections.

and then the information gets repeated for the next IT plan.

I thought it might be possible to nest data regions. After placing nested lists on my reports, when I try to associate data from other datasets onto to the nested list, the report designer UI only exposes aggregate functions like Count or First in the expression editor --> Fields collection. It does not let me associate other datasets.

If anybody can provide some details on the best approach to tackle a huge report like this, I would really apprecaite it. I am currently going with the Sub reports approach.

Thanks
Kaushal