How to use groupreq in comps.xml
 

The file comps.xml defines how packages installed in kickstart time. I try to add some code:

<group>
<id>RESTORE</id>
<name>RESTORE</name>
<description>Resilience Corporation Runtime Support Packages</description>
<uservisible>false</uservisible>
<default>true</default>
<grouplist>
<groupreq>core</groupreq>
<groupreq>RFT</groupreq>
</grouplist>
<packagelist>
<packagereq type="mandatory">restore</packagereq>
</packagelist>
</group>

</comps>

Some of the packages in core and RFT also installed before RESTORE. It seems that the groupreq have no effect. What's the problem?