I have a 50 gal gas heater and a 40 gal gas heater plumbed in parallel. I am replacing both water heaters. Right now my hot line runs out to the house and to the water coil in my hydronic forced-air furnace. Then a line comes out of the water coil and back into the drain of the first unit. I have been told these need to be separated to avoid bacteria in my bathing water. Can I run a single line to both heaters if I split the line right at the end and angle them down to both units. I know some are plumbed with a tee coming off to the first unit and then continuing down to the next unit and this can cause some issues. I was thinking of putting a tee at the end of the line and running equal distance lines to both units.