XML Schema Structures

Dear Sirs,

I  am reading the XML Schema documentation (the latest available
Working  Draft from April 7, 2000) and I have question. I need to know
if it is possible with XML Schema language to define a
type, which will allow an element to contain several different elements,
some  of  which are required, and some of which are not, in no particular
order.

Something like the 'sequence' ModelGroup {compositor}, but without the ordering
restrictions?

Or something like the 'all' ModelGroup {compositor}, but without restriction
MaxOccur = MinOccur = 1.
  
If  you  could  just answer "YES, look there" or "NO", that will be quite
enough. Thanks a lot.


Ivan Kurmanov <ivan@tm.minsk.by>.