You can do this in the Studio > Studio Setup > MIDI Ports Setup.
But I don’t see a reason for this. You can use an ASIO driver with one supplication in the given time only. But this doesn’t apply for the MIDI Ports. You can use them across multiple applications simultaneously.
@Martin.Jirsak That statement is not true. At least not on a Windows machine. There are several ASIO drivers today that are multi client capable that allow multiple applications, including the OS, to use the audio interface at the same time.
As for MIDI ports, a setup type of application, such as one referenced by OP, typically requires exclusive access to the device.
Should have mentioned in the original post, I’m working on Windows.
ASIO is not an issue, it’s just the MIDI ports, once Cubase is using them then no other windows program can.
I have an ASM Hydrasynth whose software uses the usb midi to transfer additional banks, but the ports are not available when Cubase is running.