zoned or not zoned?? thermostatic control of multiple spaces

["Lighthouse" <gruntledlark@xxxxxxxxx>]

I really wasn't sure how to title this msg. i have a building w/ 3 apts
heated by a single boiler. currently there is one unit which maintains
the thermostat.

i would like to monitor the temp in each unit, but control the boiler
from the utility room. oh yeah, and i don't want to pay for some fancy
overpriced zoning system.

it would be nice if i could do this w/ some type of wireless sensors--i
see wireless thermometers always available for about $20 or so. it
seems like there should be some way to modify these to do what i want.
i don't know enough to be able to do this on my own, but i'm smart
enough to follow instructions if anyone has some ideas.

hard-wired isn't necessarily out of the question, but i have no idea
how i might use 3 living area thermostats and set a control temp that
may not match any of them.

what i'm trying to avoid is having a single tenant freeze out or sweat
out the other two. at the other extreme, i don't want the boiler
responding to all three tenants setting their therms to 85 degrees.

i'm hoping that by having temps reported from the 3 living areas to a
"master" thermostat i can create some reasonable control. IOW, i need
actual temp readings from the remote locations (rather than just on/off
signals) so that a thermostat in an unheated basement can control the
boiler. i hope that makes sense.

any ideas? TIA.