As far as I know, having two separate sinks served by a single trap is not code compliant. You will need to replace the existing sanitary tee on the stack (inside of the wall) with a double sanitary tee.
Normally, these double tees are used for adjoining bathrooms, so you can have a sink on each side of the wall, and share the same stack. In this case, you would be installing the tee parallel with the wall, instead of perpendicular. You will need to extend each side of the tee to reach where you want the trap to be for each respective sink. In order to do this, you will need to cut a short piece of 3" PVC, and then put on a 90 degree elbow and attach another piece of PVC so it will come out of the wall. Then you can attach the trap adapter for each sink.