Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
I understand that you would like to split billing based on different users/environments.
I am afraid this wont be feasible.
ExpressRoute is charged on two basis :
- Standby cost
- Bandwidth cost
Azure ExpressRoute Circuit does not have visibility on what resource would use the Circuit bandwidth and hence, we cannot use any such filters for generating the Bandwidth cost.
Cheers,
Kapil