Ventilation for 2 bathrooms/1 roof penetration?

[nola mike]

I'm installing a bathroom directly adjacent to the existing one. The current vent exhausts air directly into my attic insulation. I'd like to remedy that, as well as install a proper vent in the new bathroom. I'd really like to only need 1 roof penetration. It looks like the way to do this is to have a central fan that exhausts both bathrooms. I would prefer to have a separate fan in each bathroom, and didn't know if there was some type of circular pipe with 2 separate chambers. So that I could have each bathroom have its own piping, but only 1 pipe going through the roof, if that makes any sense. Any other good solutions?