Azure Big IP F5 template with HA via LB

On a related note, the advice for using an Azure LB for failover seems to be to use a wildcard, network range or different ports for the VIP - but what if I have multiple *seperate* apps that use the *same* port? - if the secondary IP addresses are on a /24 subnet do I need to further subnet that to differentiate between different apps? - or should I use DSR instead?

DSR does seem to simplify a lot of this but Jeff Giroux seems to not recommend it generally.