How to select_related on reverse foreign key?

Possible Duplicate:
A left outer reverse select_related in Django?

A BlogPost has many Comments. I want to get a list of BlogPosts and all their comments.

Thus, I have

BlogPost.objects.filter(my_filter).select_related()

But the ForeignKey is on the Comment, not the BlogPost, so the select_related() doesn't prefetch any comments. Is there a way to get this to work?

I can't reverse the query (Comment.objects...) because then the other objects that the select_related() does fetch wouldn't work. I need it to work both ways.