BuddyPress.org

Nope. There’s no hidden ‘exclude’ parameter. If you really need this you can:

1) Derive a new class from BP_Blogs_Site_Blogs_Template modifying the constructor to exclude the blogs you want from the list of blogs returned by BP_Blogs_Blog::get_<whatever>()

2) Create a new template tag that modifies the standard version of bp_has_site_blogs() to call your derived template class instead of the standard one.

3) Modify your theme to use the new bp_has_site_blogs() template loop goodie.

Like this code here: http://buddypress.pastebin.com/d12aa57a1

That code is totally untested.