I'll know how that will go. Either not seeing my radio again or losing all my frequencies.
And there's probably a reason for that.
The FCC rules are exceedingly clear on this.
No one can add a radio to a Part 90 radio system without permission of the licensee. Does not matter if you have an amateur radio license, work for the company, contract for the company, know someone who works there, or "just in case". Rules are clear. You are not the licensee of this system. Unless you have direct, written permission from them, you should not be adding their system to your radio.
§ 90.427 Precautions against unauthorized operation.
(a) Each transmitter shall be so installed and protected that it is not accessible to or capable of operation by persons other than those duly authorized by and under the control of the licensee. Provisions of this part authorizing certain unlicensed persons to operate stations, or authorizing unattended operation of stations in certain circumstances, shall not be construed to change or diminish in any respect the responsibility of station licensees to maintain control over the stations licensed to them (including all transmitter units thereof), or for the proper functioning and operation of those stations and transmitter units in accordance with the terms of the licenses of those stations.
(b)
Except for frequencies used in accordance with § 90.417, no person shall program into a transmitter frequencies for which the licensee using the transmitter is not authorized.
Paragraph B makes it clear, you, as a ham, are not the licensee of this system, and you should not be programming radios to transmit on a system that is not yours.
This is why many of us run trunked systems, to keep people out that do not belong on the system. It's also one of several reasons we run encryption.
Avoid giving the hobby a black eye. Resist the urge. If you have a legitimate need to be on this radio system, you need to do it properly.