Who/what "GV Support"? There is no such thing. The help forum, linked below my name, is the official support venue. You have several issues.
Google Voice is a service, just like Gmail, Docs, Calendar, Contacts, etc. All Google services are tied to a Google account. One Google account can have up to two different inbound Google Voice numbers. When you use an OBiTALK device with Google Voice, you are granting it permission to use the Google Voice service for a specific Google account, not a phone number.
So: if you have a Google account with two Google Voice phone numbers, and you configure say, SP1 to use that Google account (a Gmail address), then all inbound calls to either of those two numbers will be handled exactly the same way: they will both ring SP1, and they will both ring any ordinary linked/forwarding phone numbers or web clients or the Android or iOS mobile apps. They will hear the same voicemail greeting. You can't separate handling of the two numbers.
If you want separate Google Voice phone numbers to act independently, you need one number assigned to one account, and the other number(s) assigned to the other account(s). For example:
Google account "A"-->OBi SP1
Google account "B"-->OBi SP2
E911 provider -->SP3.
You can configure those same three SPs on multiple OBiTALK devices, and each one will behave the same way.
Technically, you are only entitled to one free Google Voice number per account, per linked/forwarding number submitted. Creating multiple accounts to claim multiple numbers is a violation of the Terms of Use. To limit service abuse, you must submit a different forwarding phone number as an "admission ticket" to claim a Google Voice phone number. That forwarding number must be from one of the "big four" mobile phone carriers, or from a traditional land line carrier. VoIP numbers are ineligible.
This whole topic is moot, however -- while it's technically possible to enable alarm dialer support with a Google Voice SP, doing so kills the ability to use that number as a regular telephone service - touch tones won't work properly. Furthermore, most alarm companies are abandoning dial-up monitoring, since most people are getting rid of land lines. The current and future alarm monitoring technology is via a direct Ethernet TCP/IP connection over your premises' ISP (a special box from the alarm monitoring company), and/or a 4G mobile data modem with battery backup.