Failover Squid dual WAN

[killmasta93]

Hi i was wondering if someone else has has this issue before, Currently i have multi Wan failover, when my default gateway fails it goes to the second one, which works but users cannot navigate though proxy so i have to go to squid settings on advanced features on the custom options before auth i have this

http_port 3128
acl lab1 src 192.168.0.0/22
acl lab1 src 192.168.52.2/24
tcp_outgoing_address 181.57.xx.xx lab1

But what i noticed i have to change on the tcp outgoing address to the ip of the IP wan on which is working so its not automatic any ideas how i can do it automatic?

Thank you