Don't you just love the search?

http://forums.b2evolution.net/viewtopic.php?t=3591&highlight=blog+exclude

This is for excluding certain categories, but since a category is associated with one blog, it will do exactly what you want.

I was able to use this code to make this work... I no longer see the posts that I don't want - Thanks!

but I still see the listing of the blog and the category on the sidebar as part of that auto deal of categories - is there a way to get rid of that as well? I hate to seem daft?

I'm sure it's on these forums somewhere. Have you searched?