If I'm not misunderstanding, there are two issues here:
1. information for a single item is spread around the page (for layout reasons)
2. one item is contained within another in the markup (for layout reasons)
For the first problem, if you can find a common ancestor of all your
information, then you don't have a problem, just put
itemscope/itemtype on that ancestor. If that's not practical, however,
you case use itemref to "import" properties from other parts of the
page. The "vCard: Avenue Q" example in
http://foolip.org/microdatajs/live/ demonstrates this. (Warning: I
have no idea if the search engine's Microdata parsers understand
itemref, but it's in the spec.)
For the second problem, it's perfectly OK to nest items if you need
to, that doesn't imply any relationship between them. In this example,
there are two independent items:
<div itemscope itemtype="http://schema.org/Movie">
About the movie...
<div itemscope itemtype="http://schema.org/Review">It was great</div>
</div>
This is certainly wrong, because there's nothing linking the review to
the movie, per-spec Microdata parsers won't make the connection. It's
only if you use itemprop on the inner item that it "belongs" to the
outer item:
<div itemscope itemtype="http://schema.org/Movie">
About the movie...
<div itemprop="review" itemscope
itemtype="http://schema.org/Review">It was great</div>
</div>
(Note: I havent' checked if review is a property of Movie, just giving
an example.)
--
Philip Jägenstedt