Router without server

I'm at a loss because I'm searching for the wrong search terms.

In our new building, we will be subleasing to three or four other small businesses (almost in an executive suites setup). I think what I want is a router that lets me provide them internet access without letting them see other computers from another business.

My business has no need of an onsite file server--we are 100% cloud.

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1. Is it a thing to have a router that can set up VLANs without needing a dedicated server? If so, when I look at routers, what is that feature I'm looking for called or where can I read more?
2. As a bonus question (for me!) (that may be in the explanations I should be reading but can't find) I was going to put IP phones on one VLAN, the shared printer on another, and each of the businesses respective computers on their own VLANs. If I want to be that complicated, where everyone can "see" the printer but can't "see" other businesses' computers is that exactly what a dedicated server is for? Am I blinding myself in thinking of servers primarily as file servers?

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(rambling at this point: given that my firm has 6 users, and the tenants will be 1-4 users each, is the answer to just get cheap residential-grade routers for each tenant that separately connects to the modem and then if they want to print to the shared copier they either put it on a flash drive or I try to set up email to print?) (Taking that a step further, I could just give them access to guest wifi and make it their problem if they want to secure themselves from other people on the guest wifi.)

(my business is a law firm in a type of law where data privacy is a bigger concern than other law firms apparently think of it)