I'm trying to add a sink next to an existing bathroom. Sink will be probably 3 feet from shower vent pipe. Floor is a concrete slab so all existing drains are underneath. I'd like to minimize busting thru concrete. The picture below is a pretty good representation of the existing piping, except for the pipe below grade that are probably running horizontally.
Can a sink drain/vent into a nearby shower vent pipe (e.g. connection in red on the picture)?
If this is not allowed, what's the best solution here?