Advertising specific routes from a subnet

Running Tailscale 1.42.0_4.0.29 from Truecharts on TrueNAS Scale, version 22.12.2

I have a simple TrueNAS scale setup that I can successfully access through tailscale using subnet routing, advertising the route 192.168.15.0/24. This unfortunately means that users accessing this NAS also have the ability to access printers, my router and everything else. How would I go about specifying IP’s on the local subnet, one at a time? eg, 192.168.x.x and ONLY that adress.

Subnets are specified by CIDR block in Tailscale configuration.

In CIDR notation, a /32 block refers to a single address.