Lufthansa
For what it's worth, you might start with Airline Training Center Arizona Inc. , 1658 S. Litchfield Rd., Goodyear, AZ 85338, telphone number: (623) 932-1600. ATCA primarily trains Lufthansa crews, but it was taking self-funded students for a time. It may not anymore, but maybe a phone call might steer you in the right direction.
Another Lufthansa affiliate is Airtransport Training International (ATTI), 6400 S. Aviator Lane, Tucson, AZ 85734, telephone number: (520) 578-4000. I recall that it played second fiddle to ATCA. But, you can still call them.
One other suggestion is where I worked at one time,
FlightSafety Academy. FSI has done a lot of foreign airline contract training. However, most of the time, the trainees earn U.S. Commercial-Instrument-Multi certificates and convert them when they return to Europe. Just an idea, but expect a sales pitch rather than a lot of help.
Don't expect a lot of luck here in the U.S. I doubt there are many schools here that train off-the-street students for non-U.S. certificates. Those that do primarily do contract foreign airline training.
Hope these ideas help. Good luck with your efforts.