you can have the AA answer every call. You can record your custom options for the callers. Pressing 1 will continue the call as configured on the Obi, so if you use the Obi to fork calls to multiple phones the call will continue as configured.
You do not have to present the callers with every option. You can record prompts for only 2 options but tell your trusted callers the prompts that aren't announced (press 2 to make a new call), and of course use the pin for security.
Of course this would take the google voicemail out of the loop. A home answering machine would then take the calls. You can even have the Obi dial a designated number if no option is selected. you could have the Obi call your google voice number again, using a different trunk, and have your google voice set to always send that number to voice mail. So telling the caller to just wait to be delivered to voicemail would work.