GTM Globalbal availability

We have 2 vips in different data centers. 1.Vip-ds1 2.vip-ds2

1.We want GTM to respond vip-ds1 always and incase if it is down should give out vip-ds2. We all know Global availability take care of this requirement. 2.If we see vip-ds1 goes down,we want GTM to respond just vip-ds2 even after vip-ds1 come back up. We want to enable vip-ds1 in a contrlloed manner as we already failover once.We dont want user sessions to go back to vip-ds1 again causing another failover once vip-ds1 is up again. We want to do it in more controlled manner.

GTM pesistence is in my mind to keep TTL to whatever timeframe we want to keep within that data center vip for established sessions. What are the other options we have here. Any thought process is much appreciated.