Tripple "T" Wye not?

I’m looking for some opinions on this flue set up. The two flue pipes on the left come from 2 natural draft hot water heaters and the other comes from the furnace at the bottom. All 3 flues connect with T’s and I’m concerned about how the furnace flue is across from the hot water heater flue. I would appreciate some input here.

Typically, the smaller vent connector pipe is above:…pendix%20B.pdf

…and the chimney vent pipe may be of insufficient size, etc.

It is worth calling out.