nnimap-split-inbox, spam-split and multiple inboxes

[Richard Riley <rileyrg@gmail.com>]

If someone has imap splitting working for multiple imap accounts couuld
you please share your settings. I wish to use the spam-split
functionality to auto move bogofilter detected spam to a temporary spam
holding area.
 
I have 3 inboxes displayed as 

nnimap+accA:INBOX
nnimap+accB:INBOX
nnimap+accC:INBOX

Is it possible to split on the three? nearly all examples I have seen
split a single INBOX

(setq nnimap-split-inbox "INBOX") 

Can splitting work for three? Any pointers/suggestions appreciated.

I turned up the verbosity for Gnus and dont currently see any splitting
activity.

I do have:-

 '(nnimap-split-rule (quote nnimap-split-fancy))
 '(nnimap-split-fancy (quote (: spam-split)))

and 

 '(spam-mark-ham-unread-before-move-from-spam-group t)
 '(spam-mark-new-messages-in-spam-group-as-spam nil)
 '(spam-regex-headers-spam (quote ("^X-Spam-Flag: YES" "X-Bogosity")))
 '(spam-split-group "Gnus-Spam")
 '(spam-use-bogofilter t)

So spam-split should be using bogofilter to identify spam mail and
moving them directly to Gnus-Spam.

In the group settings for my INBOXs I set them as HAM groups since
anything passing the splitting ought to be considered ham. Is that ok?
The exit processors do correctly move any emails I manually tag as spam
to the spam pen.