[Zope-CMF] Efficient way to get replyCount

[Zopista]

On the home page of ZopeZen I have a list of articles and want to display
the reply count for each article. Its there now, but I did it in a hideous
way, I go and get each message (using restrictedTraverse) and then call
replyCount on talkback of each object. It works but its hideously expensive.
Since replyCount isnt exposed anywhere else, I just can see an obvious way
of doing this quickly, is there one?

Cheers.