GTM and DSC Sync-Failover with more than two members

As Cory mentioned DSC is not to be confused with a GTM sync groups. In your configuration you want to build out your GTM sync group to include all devices licensed with GTM. Keep in mind that all GTM's in a sync group are active. This is done by performing BIGIP_ADD and GTM_ADD between all of your GTM devices.

The sync group's configuration will reference your LTM virtual servers which will be hosted by whatever LTM device is currently active.

For more information see the GTM implementation manual:

http://support.f5.com/kb/en-us/products/big-ip_gtm/manuals/product/gtm-implementations-11-1-0/15.html