Is my landlord required to separate utilities between garage apartment tenant & main house when sharing meters?

Our landlord lived in the garage apartment when we moved into main house 3 years ago. Utilities were shared, and we agreed he would pay for our internet in exchange for his share of utilities. He moved, rented the apartment to someone, and we verbally agreed upon her paying a certain percentage of bills directly to us. We are tired of dealing with apartment tenant and no longer want to bear the burden of copying/calculating/collecting each month. Landlord has agreed, via email, to separate utilities, but has not yet figured out exactly how. He'd like to have separate meters installed, but we don't see how that will be possible, seeing as we are allowed usage of garage- which would be connected to apartment's meters. He has not included this in lease renewal- it says we pay utilities.