Group Uptime Reporting

Hello:

Is there a way to change the availability reports for monitoring groups so that if 1 server in the group is down for 10 minutes that the group will get an appropriate weighted downtime?

Instead of the following:

1 server out of 20 down for 10 minutes out of 30 minutes gives group a 33% downtime

Something like this:

1 server out of 20 down for 10 minutes out of 30 minutes: 590 minutes (600 minutes total up - 10 minutes total down/600 total minutes (20 servers * 30 minutes) = 98.33% uptime for those 30 minutes

Is there a way to make reports work like this? If not, I think there should be.

Thanks,

Aaron