RDS Gateway access from failover link

I have W2K8R2 RDS Gateway accessible from Internet via  primary IP address and FQDNhttps://rds.mydomain.com. Firewall has failover Internet connection with different ISP, diff  IP address  and FQDN https://rds1.mydomain.comthat kicks in when primary connection goes down. Both IP addresses point to the same internal RDS server IP address

Is it possible to set RDS to accept backup connection when primary  link goes down (Use these gateway server settings: server name rds.mydomain.com& rds1.mydomain.com) or I have to deploy additional RDS server for rds1.mydomain.com?

Thanks

Wilson