This feature apparently has already been implemented long time ago, however it's not included in any of the izPack releases and can't be found: http://developer.berlios.de/feature/?func=detailfeature&feature_id=642&group_id=1408

I coded another implementation and commited it to the SVN. It uses the following syntax:

<pack name="2" installGroups="1" required="no">
 <description>dscr</description>
 <fileset../>
 <depends packname="3"/>
 <excludes packname="1"/>
 </pack>

The "excludes" tag is symmetric to the "depends" tag. Packs declared in "excludes" are being unchecked when the parent pack is checked. This is slightly different from what was proposed in the izpack dev mail list, but I think it's better this way.

Any comments or suggestions?