Did LTM have Bandwidth threshold irule checking?

Hi

 

[example scenario]

 

We have two internet link. First link speed is 10Mbps. second link is 5 Mbps Normally we using First link as primary and LB method is priority group. Now we need second link active when Primary link bandwidth using more than 9 Mbps.

 

Is there anyway to check bandwidth threshold of first link? if it's irule. it will be like this

 

if { bandwidth > 9 mbps } { member second_link }

 

Or i have to use another feature . or it can't be done? Thank you very much