Force the External Mode

Hello there!

I am using a UR3e in a setup with a PLCnext by Ethernet (profinet) and I was wondering whether I could set the robot to external mode. Now I know how to enter this, however, it is only two buttons to exit this mode again. Is there any way to prevent this, for example setting a password there like with the automatic mode?
Basically we want to have our construction being able to funciton unsupervised, so that a potential user cannot do anything but start or stop a preset program, optionally by pressing external buttons or commands from the plcnext.
Is there any way to make this work other than removing the Teach Pendant?