You can have multiple Google Voice numbers, each on a different Google/Gmail account, registered on multiple OBiTALK devices. The devices should all be connected to one OBiTALK account.
I prefer not to use my Google account as the sign-in credentials for OBiTALK. The risk is if you forget you've done that, and down the road delete that Google account. Instead, sign into OBiTALK using a username and password (and obviously, don't lose it).
Pick one existing OBiTALK account, or create a new one with a username and password. Delete the devices off of the OBiTALK dashboards on the other accounts.
Sign into the Google accounts and delete the "OBiTALK Device" entries from the settings page (
https://voice.google.com/u/0/settings).
Go to your Google account settings and delete the Google Voice/OBiTALK service permission off of each account (see the screenshot below):
https://myaccount.google.com/permissionsMake sure all three devices are on firmware 3.2.2 (Build: 5921EX).
Add all three devices to one OBiTALK account. Verify that each one can call the echo test number (**9 222 222 222).
Do all of the following steps from a desktop/laptop web browser. If you're using Firefox, press Ctrl-Shift-P to open a private browsing window. If you're using Google Chrome Browser, Microsoft Edge or Safari, press Ctrl-Shift-N to open an incognito window. This is important, to avoid having multiple Google accounts signed into the same browser at the same time.
Sign into the OBiTALK account, then press Ctrl-T to open another incognito/private browser tab in the same window, and sign into the correct Google account.
Configure all three Google accounts on three of the SPx slots on each device, one device at a time. Each time you do this, close and re-open the incognito/private window, again, to have only one Google account in the browser's cache.
This only works for consumer
gmail.com accounts; Google Workspace (formerly G-Suite) accounts won't work.