Trying to figure the easiest way to have a single printer shared by 3 or 4 organisations all located on the same building level.

At the moment they all use one of the organisation's network to a dedicated PC acting as a print server using PaperCut software.

This is bad having all the individual networks possibly being able to interact with each other, so looking to separate them.

With ignorance of such networking matters my thought was having each of the 4 routers being fed into a switch, and the switch cabled to the PC/print server .... would that actually work for any of them to print but keep each network isolated from the others?

Any other thoughts without the expense and oversight of a managed switch?

Tks.