XSD choice inside all

You can't put choice tag inside the all tag. So, is there any workaround to get this functionallity? For example, I have<settings> tag like:

<settings>
    <logging />
    <sending />
    <useonly />
</settings>

Or something like

<settings>
    <logging />
    <notuseonly />
    <sending />
</settings>

So I want to prevent <useonly> and <notuseonly> showing up together, while the order is not important. And if allowed, in XSD it would look like:

  <xs:all>
    <xs:element minOccurs="0" maxOccurs="1" ref="sending" />
    <xs:element minOccurs="0" maxOccurs="1" ref="logging" />
    <xs:choice>
         <xs:element minOccurs="0" maxOccurs="1" ref ="useonly" />
         <xs:element minOccurs="0" maxOccurs="1" ref ="notuseonly" />
     </xs:choice>
  </xs:all>

Any thoughts?