Can XML Schemas do this?

[Brian Burridge <maillist@burridge.net>]

I have an xml document, where we want elements to be able to appear in
any order. Some are required, others aren't. And in many cases if you
have tag A then you don't need tag B, and vice versa.

Problem is, I need to use the ALL tag and have choices and groups within
it, but you can't.

Is there a way around this?

Brian Burridge