In my Schema File I defined a Group with a Sequence of possible Elements.

<group name="argumentGroup">
    <sequence>
        <element name="foo" type="double" />
        <element name="bar" type="string" />
        <element name="baz" type="integer" />
    </sequence> 
</group>

I then reference this Group like this:

<element name="arguments">
    <complexType>
        <group ref="my:argumentGroup"/>
    </complexType>
</element>

Is it possible to reference the Group at some other point but restrict it so it's a Choice instead of a Sequence. The position where I want to reuse it would only allow one of the Elements within.

<element name="argument" minOccurs="0" maxOccurs="1">
    <complexType>
        <group name="my:argumentGroup">
            <! -- Somehow change argumentGroup sequence to choice here -->
        </group>
    <complexType>
</element>