Can two LEDs attached to different pins share their resistor?
Your circuit is safe from the electronic viewpoint, so long as the LEDs used can withstand a back-emf of 4v or so. 

If only one LED is on at a time, all will be sweet. But if two or more are on, the brightness will drop and the brightness between LEDS will probably be inconsistent. The forward voltage drop of individual LEDS tend to vary a little, so one is likely to hog most of the available current. 

A separate resistor per LED is probably best.