I'm try to design a XSD schema that allow elements to be in a random order and have maxOccurs="unbounded".
My XML:
<root>
<key></key>
<group></group>
<group>
<key></key>
<key></key>
<group>
<key></key>
<key></key>
</group>
</group>
<key></key>
<key></key>
<group>
<key></key>
<key></key>
<key></key>
</group>
<key></key>
</root>