I have done something like this before but it was for opening multiple lockers using only one reader.
I don't think I would reccomend doing this on an elevator as this uses global IOs. so if your gateway loses connection to the server for any reason you will lose access to those floors. If you do want to use global IO's to accomplish this on an elevator you may want to think about putting in a key switch that will bypass your outputs in case of server failure/communication issues.
Here is what I did.
I created a door with just the reader. no outputs.
I created generic outputs for the outputs.
(In my situation we were not using the hot stamp on the badges for anything so I was using this field as an identifier for the outputs.)
I set up a global IO that first checked for a grant access on the door with the reader and then checked for the hot stamp.
I created 2 global IOs:
One that checked for a grant access on the door and for a hot stamp of 2. then activate the output for button 2.
Then one IO that checked for a grant access on the door and for a hot stamp of 3, which would activate the output for button 3.
Even if the badge has access to the elevator it will not activate the outputs unless you have the hot stamp set to 2 or 3.
