Using Active/Standby for different traffic groups

Greetings,

I would like to ask you folks something that we are having trouble deciding. One of our customers wants to change our Active/Standby deployment. What we want is that, by using two different traffic groups, we would like to use our appliances as Active/Standby for relevant traffic group but both devices will be processing traffic for a different traffic group. So basically one of the appliance will be Active for traffic group 1 and the other appliance will be Active for group 2. When one of them gets into trouble, it will fail over to the Standby device in the relevant traffic group. This way we won't be losing our HA architecture and share the load of Virtual Servers between these devices. We would like to ask your opinion about this change in their environment. Thank you for your time in advance, highly appreciated.