If you do not have the capability to calibrate pressure gages in house (using a NIST traceable master), and you can not locate a local "certified" calibration house, it is acceptable, per QS 9000 third edition, to use the gage manufacturer. They do not have to be certified, just traceable to NIST. Also, the certificate of calibration must meet the requirements of QS 9000 (e.g., before and after data, NIST traceable numbers of masters used, procedures used, etc.)
I calibrate most of our pressure gages in house using dead weights that are calibrated by the original manufacturer. I do have several high pressure gages (3k - 5k psig) that are sent out annually back to the manufacturer for calibration.
I do know of several other gage calibration sources located in North Carolina. I found them through the gage houses that I do business with. You might want to ask the people you buy from if they know of anyone. Also, the Thomas Registry is on line now, and is a free access.