FedEx for international orders only

Hello!
Thank you everyone for all the wonderful support on this board.

I've been trying to look for this answer but no luck, so here I go.

I have installed the USPS module and FedEx module. I want to offer my local customers with shipping by USPS (no FedEx), and my international customers the option of both, USPS and FedEx, but something is not working.

I have FedEx shipping zone set to International which includes the countries I'm shipping to and according to the specifications:
"Shipping Zone
If a zone is selected, only enable this shipping method for that zone."
Well that's not happening, both boxes for ground and express still show despite this and I would like to eliminate them completely if the customer is located in the US.

Anyone has any idea how to fix this??

Thank you for any help! :dontgetit