Netting two contract accounts

Hi,

I have two installations that are some distance apart. Installation A has a consumption meter (one register). Installation B has a net meter (two registers) as it has a solar panel. Both installations have meters read hourly. The business partner that owns both installations would like to receive a bill that covers both installations, but NETTED. This means that meter at installation B is netted (consumption - generation) and if that shows net outflow then this needs to be netted against meter at installation A. This netting needs to happen at hourly meter read level. I guess I can produce a consolidated/summary bill for the customer across the two installations, so that will net them at that level, but how do I net two registers on the same meter that has hourly meter reads, to give me hourly consumption/generation at installation B?

Thank you,

mike