Custom property to Interfaces

Hi All,

I am newbie to NPM.

I need to set a threshold performance alerts to some newly set interfaces (around 9 -10 interfaces). (alerts and email)

Before i am setting the thresholds in advance alert manager, i am creating a custom property for these 10 interfaces.

But after i create the custom property by seleting these interfaces.. when i view the values for these defined custom property, it is showing me all 11000 interfaces instead of 10 interface.

Please sugest, if there is any better way to create threshold interface utilization alerts.