Venting a bathroom

[Fred Woods]

I want to vent my new upstairs bathroom and laundry into the 3" main through the attic.

There will be a washing machine, shower and separate bathtub. Can I use a 1 1/2" vent for each and connect them together in the attic and then to the main 3" stack

 

[Terry]

The washer, shower and tub can vent with 2" can revent in the attic.
A toilet would need 2".
Any waste from that bathroom would need to tie in lower than any waste below it. None of that could come in above the vents from below.