I've written a script (needs tampermonkey) to automatically fill the next Bitcoin address (which is your multi account) when you logout and automatically show the captcha modal after login, but you need to type the captcha which I cannot do about at my current knowledge. If you want to add any btc addresses for login, just a simple entry in script is needed, nothing else.
Keep in mind, it's not a automatic captcha solver, it'll just reduce your work of copy pasting the address everytime for each login. You'll be banned if you use all other accounts as referrer feeder.
As it's advertised as a Ponzhi scheme, so I think it wont be a problem in doing this.
P.M if you need to try it.