Anyway to add new groups into bloodmoon

[lasse11121]

i have been trying to customize the bloodmoon with Snufkins server side zombies, but only wanted 1 boss on the hordenight choosing 1 of the bosses from a group.

been trying this code in the gamestages.xml: 

<configs>
    <append xpath="/gamestages">
        <gamestages stage="1">
            <spawn group="ZombieBosses" num="1" maxAlive="1" duration="4"/>
        </gamestages>
    </append>
</configs>

and in the entitygroups: 

<configs>

    <append xpath="entitygroups">
        <entitygroup name="ZomieBosses">
                <entity name="zombieCowhead"/>

                <entity name="zombieUndertaker"/>
        </entitygroup>
    </append>

</configs>

but it seems the feralHordeStageGS# is overwriting it.

anyone tried messing with this?