High Availability - Speed Fusion VPN

I’d like to use high availability function between 2 peplink units with minimum downtime.
On the slave device I can select “Establish Connections in Slave Role” and my WAN connections are active all the time, therefore faster to switch.
My problem is, while this is ok for non VPN connections, it creates a “Route conflict” in Speed Fusion VPN connections, as both units have to be in the same Subnet to enable High Availability mode.
Can you recommend any solutions ?