It looks as though this is supported - see extract from the SRDF agent guide (https://sort.symantec.com/agents/detail/5520:(
Considerations for using the agent in concurrent or cascaded SRDF configurations
You can configure the SRDF agent to manage a concurrent or cascaded SRDF
configuration. The agent automatically detects the underlying configuration and
takes decisions during failovers.
The present behavior of the agent is that if there are more than two sites involved,
the agent manages failovers only on the SYNC links. The agent always makes sure
that the devices that are local to the host on which the resource is online, are in a
primary (R1) role. The agent switches the SRDF configuration from concurrent to
cascaded and vice versa. The agent automatically detects the underlying
configuration and requires no manual intervention.
There is more information and diagrams in the doucment.
Note from a VCS perspective this should be fine - it is the replication agent that needs to support 2 replication targets which the SDRF agent guide says it does