i understand in 11.4.0, we can specify next active device (an alternative to load-aware failover).
Ordered failover lists for Sync-Failover device groups
An alternative to the new load-aware failover feature is an ordered list. For each traffic group in the device group, you can specify a list of devices that you want to be the next-active device for the traffic group if failover occurs. If the first device in the list is unavailable, the BIG-IP system chooses the next device in the list to be the next-active device, and so on. This feature is more useful for homogeneous, rather than heterogeneous, platforms in device groups.Release Note: BIG-IP LTM and TMOS 11.4.0
http://support.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnote-ltm-11-4-0.html