I can import Group Properties for the I-DHCP Enforcer, so i added in a dummy mac address (44-44-44-44-44-44) and it added this line to the XML. If it was just a simple case of updating the XML with the 600 MAC addresses and importing it back into the SEPM this wouldn't be a problem but i can't understand what the rest of the items are in the line,
i.e. what is the <MacAddress _d="false" _i="BEB2A3B00A01300D01BDBFECE7F3232A" _t="1245144919489" _v> part mean?
<MacAddress _d="false" _i="BEB2A3B00A01300D01BDBFECE7F3232A" _t="1245144919489" _v="4">44-44-44-44-44-44</MacAddress>