Splitting gas lines on a 2 family house?

[Tyler Brown]

I've got a (legal) 2 family house in Queens.  Right now, the electric is split and the tenants pay for their own usage, while I pay for the water and gas for the whole house.

All the water bills for 2018 added up to about $600, so I'm not really concerned with that.  However I spent about $2,000 on gas.  Has anyone ever had the gas lines split, so that each tenants will have their own account with the National Grid and pay for their own usage?

I'm sure it won't be cheap, but even if it's $10k, that'll pay for itself in 5 years.

I'd also be interested in splitting the water too, if it was really cheap to do so, but I'm assuming that at a savings of only $600 a year, it'll take an unreasonably long time to pay for itself.