Hi Guys, is it possible to separate the upstairs heating and hot water for showers etc. from the downstairs basement?

Presently the basement is unimproved. I presently have only one thermostat in the entire 1950's ranch style house. I eventually want to rent out the basement. I am about to get a natural gas line from the natural gas company installed. Presently, I have an older Weil McLain oil burner which works well. It looks kind of smallish and I believe it was installed in 1987. Not sure how much longer the oil burner boiler will last. I have hot water cast iron radiators in the upstairs and in the basement. The oil burner heats the hot water (with a coil). I guess I should get rid of the oil burner and take advantage of the incentives the natural gas company is offering, although the incentives apparently end in June. Not sure if I will be able to take advantage of the incentives before the offer expires.

So I did some research and found out there is a meter that can be installed after the natural gas company's meter. That way the basement could pay for their own consumption of natural gas. Apparently after doing some research there is a way to measure electricity also, after the electric company's electrical meter. I was thinking I could possibly have an electrician install a separate tankless heater for hot water for the radiators and shower etc. in the basement. Or I could just have one boiler or tankless installed for the entire house, upstairs and downstairs rental, but I am unable to figure out how to separate the consumption of natural gas for the basement, as opposed to the upstairs if only one boiler or tankless is utilized?

Thank you. I would appreciate your insight and opinions into this matter.