Would it be possible to make or print parts to enable a single ventilator support multiple patients?

A few studies suggest it could be done: https://www.ncbi.nlm.nih.gov/pubmed/18164798 https://www.ncbi.nlm.nih.gov/pubmed/16885402

Could be faster than building new ventilators.

You usually "tune" the ventilator parameters to each patient, so they'd have to be fairly similar size, need, etc.

Too much volume (or pressure, depending on the control mode) can injure the lungs, too little and you're not addressing the underlying problem very well.