relevant element within repeated element

Hello,

I have a schema for which I am building an xforms document.  The
schema calls for a repeated complex-content element (attr), within which there
is a choice (attrdomv/edom | attrdomv/rdom etc) of one of four complex-content elements.  I want to 
allow the user to choose between the four, leaving the other three
as irrelevant at submission.  This should be available for each (attr) element in
the repeated element group (ignoring the need for a repeated "detailed" element).

Does Xforms support such functionality?  What would be the recommended
method to achieve this?   I note that switch/case within repeat is
not supported in Xforms 1.0, and there appears to be no mention of this
in Xforms 2.0. In any case, I'm not certain that swictch/case would be
a desired mechanism, because not only would I like to hide the complex
content of unselected choices, but I would not want to submit them either;
I'm not clear on how the relevant model item property is manipulated for 
unselected cases.

Any light this group could shed on the matter would be appreciated.

Peter Rushforth
613-951-3890 | facsimile / télécopieur 613-951-0569
Peter.Rushforth@statcan.ca
Statistics Canada | 120 Parkdale Avenue Ottawa ON K1A 0T6
Statistique Canada | 120 avenue Parkdale Ottawa ON K1A 0T6
Government of Canada | Gouvernement du Canada