How to create a multi-seat with one graphics card (having three DisplayPorts / HDMI)?

I am planning to build a reasonably powerful PC, for my needs (scientific calculations, as well as general computing needs; no gaming). And I will have a couple of collaborators coming to join me. I have realized it could be useful to have a multi-seat Linux operating system. If I understand correctly, a multi-seat operating system allows all users to work independently (with their own monitor, mouse and keyboard) and concurrently. However, when I look for documentation, I see lots of old webpages, and the information is a bit confusing (to me, at least). For example, I read the statement that each user needs a graphics card. But for example, if we have a single GPU, and this GPU had 3 DisplayPorts (or HDMI), couldn't this GPU be used for the three users? Note: I have read Zephyr allows to have a multi-seat with a single GPU, but I want to avoid third-party applications, I would like to rely only on Linux. If it is not possible, has anybody tried a Threadripper (or any other board with enough PCIe lanes) with say 3 passive, low power GPU, like the nvidia GT 730 for example? Edit: I have changed the word "multi-user" for "multi-seat", given a recommendation in the replies (thank you).