Default representation of a choice structure

Hi!
I've the following snippet in my schema:

<xs:element name="MyElement">
<xs:complexType>
<xs:choice>
<xs:group ref="First_Group" />
<xs:group ref="Second_Group" />
</xs:choice>
</xs:complexType>
</xs:element>
When clicking on "Recreates a default representation from the schema",
how or is it possible to choose between the two groups rather than generating them both?

Thank you.