Problem with yum groupinstall...

I have the following two groups in comps.xml for my repository.  When I 
perform the following command:

yum groupinstall 'Bridgeways Core Development'

I was expecting the packages in the groups bw-core-devel, 
bw-core-depends and base-x to be installed.  However, the packages from 
bw-core-depends are not installed.  I'm using yum 3.0.1 on RHEL5.1.  I 
have been unable to find much info on the xml tags in comps.xml.  Do I 
need to set <default>true</default> in the group bw-core-depends to get 
this to work?

 <group>
    <id>bw-core-depends</id>
    <name>Bridgeways Core Development Dependencies</name>
    <description>Packages required from a distribution to build 
Bridgeways core.</description>
    <default>false</default>
    <uservisible>false</uservisible>
    <biarchonly>false</biarchonly>
    <grouplist>
      <groupreq>base-x</groupreq>
    </grouplist>
    <packagelist>
      <packagereq type='mandatory'>autoconf</packagereq>
    </packagelist>
  </group>

 <group>
    <id>bw-core-devel</id>
    <name>Bridgeways Core Development</name>
    <description>Packages required to build Bridgeways core.</description>
    <default>false</default>
    <uservisible>true</uservisible>
    <biarchonly>false</biarchonly>
    <grouplist>
      <groupreq type='mandatory'>bw-core-depends</groupreq>
    </grouplist>
    <packagelist>
      <packagereq type='mandatory'>libmwn-devel</packagereq>
    </packagelist>
  </group>


I've shortened up the package lists in the groups for brevity.  Any 
ideas on what I'm doing wrong?

Scott