Customer groups are related to campaigns. You can use the
customergroup.xsd schema with promotions.
The following sample XML contains a campaign (without actual promotions) that has two customer groups.
<campaign campaign-id="c1">
<description>A sample campaign.</description>
<enabled-flag>true</enabled-flag>
<start-date>2008-01-17T11:04:24</start-date>
<end-date>2008-01-17T11:04:31</end-date>
<customer-groups>
<customer-group group-id="gold-customers" />
<customer-group group-id="platinum-customers" />
</customer-groups>
</campaign>