It went pretty good for the first 10-20 or so groups but now I get the multiples of the really annoying captchas (click until none remain) per group...
Damnit yahoo...
update: just enabling the vpn was enough to 'reset' captcha to the simple level, seems like yahoo does not take into account whether your IP is 'residential'.
I also noted that for yahoo changing IP, even changing continents, allowed me to use the same cookies as long as I kept my original browser window open.