Cost/Referrals - Splitting hot water & gas utilities on a duplex

[EDWARD M.]

I just recently purchased a two-family home with just electricity being paid by tenants. I am looking to split the hot water and gas utilities to be paid by tenants, too. I have one furnace and one water tank and I think I have more than enough space to fit a second of both. Any idea how much this would cost? Steps? Advice on whether I need a second furnace at all or not? Any referrals?