Is there a way to group “ elements?

Have you considered nested UL’s? I believe this would validate:

<UL>
    <LI>
        <UL>
            <LI></LI>
            <LI></LI>
            <LI></LI>
        </UL>
    </LI>
    <LI>
        <UL>
            <LI></LI>
            <LI></LI>
            <LI></LI>
            <LI></LI>
            <LI></LI>
        </UL>
    </LI>
</UL>

Your CSS trick was my first guess; too bad you can’t use that.