Suggestions for sub-mixing external instruments...?

Hi all,

So even though I have 24 analogue inputs, the amount of external MIDI kit I’m trying to pipe into Cubase would need quite a bit more than that.

I’m currently sub-mixing via an analogue desk, but setting up an external instrument for this is proving to be cumbersome. I don’t think there’s an option for instruments to share inputs.

Does anyone have suggestions for a good way to work in this scenario? Should I perhaps ditch the external instrument idea completely and use straight audio inputs, recording and adjusting timing later-on?