Unity Connection 9 Failover Not Working

Question

Just built 2 Unity Connection 9 in Pub/Sub configuration.  Call Manager version is still 8.
Call Manager configuration:
1 line group, 1 hunt list, and 1 hunt pilot
1 voicemail pilot and 1 voicemail profile
64 voicemail ports (32 ports per Unity Connection server) (all ports are registered)
Unity Connection configuration:
1 publisher and 1 subscriber
1 phone system
1 port group (64 port count, 32 for publisher and 32 for subscriber)
Cluster configuration is set to change status when publisher fails
Publisher takes calls without a problem.  But when publisher stops taking calls, subscriber does not take the calls (busy signal).
To test if the issue might be on the call manager, I changed all port settings in Unity to point to the subscriber.  Subscriber take the calls.
I changed 2 ports to point only to publisher, publisher takes the calls.  But when publisher stops taking calls, subscriber does not take the calls (busy signal).
It seems like I cannot split the ports to both servers.  Am I missing something?
Has anyone encountered this issue?  Any info is appreciated.
Thank you!

Answer 1

Problem solved! 
In Call Manager, I created a second line group for the subscriber ports.  Added the second line group to the hunt list.  Set the LG for the subscriber in the hunt list as first and publisher as second.  This way, all calls will go to the subscriber server first.  
In Unity Connection, I created a second port group then added the ports and made sure they are registered in CM.
Tested failover by stopping taking calls on each server and it works!