SCOM monitoring of DHCP scopes

We have a bit of an issue with DHCP scope monitoring in our environment, which I am pretty sure SCOM could do better, but I just haven't found it yet.

We have all our DHCP scopes split, for redundancy and DR, but we don't have them load balanced due to how our DHCP was originally setup. What we are seeing is that one scope will dish out all its leases before the other scope hands out any. So as  result SCOM is constantly alerting for scopes being low or out of addresses, while the associated scope all have all its addresses. I am trying to find a way to have SCOM monitor the two scopes as one. I thought I could use an aggregate rollup monitor, or a dependency rollup monitor to do this............... but it looks as though I am clearly not up to the task. Has anyone seen this issue before and do you have any suggestions for how you tackle the issue of having SCOM monitor 2 DHCP scopes as one scope?