Audio Input from Fe-Pi

I have a fe-pi dac that has line input, line output and headphone output and was wondering if anyone has ideas on how I could pass the line in through volumio. Reason is I have the volumio Pi connected to a single input amp and would like to switch between the volumio music and a passthrough on the line input. If I connect to the headphone jack I can manually switch between DAC and Line_In using Alsamixer but I would like to do it on the line out connection and through volumio itself.

experimenting and if I issue the command

alsaloop -C hw:1,0 -P hw:1,0

I can get passthrough from the line input to the line output. So my next question, How can I integrate this with volumio so that I can switch between playing music and passthrough?

I’m super interested in this as well!