One physical connection three dhcp leases

Behind my RB2011, I have three types of traffic: traffic from my workstations, traffic from my servers, and traffic from clients on wifi. In front of my RB2011, there is a UTM and it rather annoying to have one policy I enforce on all traffic coming from t he RB2011. What I would like is for the UTM to see three seperate IPs from the RB2011 such that I can enforce seperate policys for each.

So in effect, I would like something similar to the following: 3 virtual lans behind the RB2011 that each have their seperate DHCP lease from the UTM.

I’m not sure how to accomplish this short of having three physical connections to the UTM and creating bridges with the port going to the UTM and the the port from which the traffic from the aforementioned devices is coming from.

Have 3 different IP addresses assigned to the interface between the 2011 and the UTM on the same subnet, then use the action of src-nat instead of masquerade to specify what each subnet gets NAT’ed out of.