Monitoring VOIP Call Centers

How would you organize monitoring for VOIP Call Centers across the country, by services or locations.
Example 1: Matrix by Service
Alert indicating alarm on gateway.
Drill down a level and see alarm in on media gateway. Drill down another level and see alert is in New York. Call out to appropriate party.
Example 2: Matrix by Site location
Alert indicating alarm in New York. Drill down and see Media Gateway alert. Call out to appropriate party.

thanks