Delt with a simmilar issue a while ago. Auxilliary stacks were not installed and the basement bathrooms were connected too close to the bottom of the stack (containing suds). Rule of thumb here for high rises is your first horozontal connection should be 10' away from the stack.
No one wanted to spend money, so to solve the problem we installed check valves on the fixture outlet pipes for the sinks. Temporary solution that is still working.
Never give in. Never give in. Never, never, never, never--in nothing, great or small, large or petty--never give in, except to convictions of honor and good sense. Never yield to force. Never yield to the apparently overwhelming might of the enemy.
- Winston Churchill