it seems that this is a newer feature that should be available in our current bugzilla, but i guess it just has to be turned on ? http://bugs.gentoo.org/page.cgi?id=fields.html#See_also you can see it in action here: http://sourceware.org/bugzilla/show_bug.cgi?id=12489 look in the upper right under the CC list
err i'm stupid ... it's under our customer "Arches" list which is why i was missing it