You have a bar at the bottom of your screen that is used for the exp required. (Mine says 18000/18000) If the experience pack is empty, you use the amount that is required (200 exp/ 1000 exp). If its a "Full" EXP pack, then its basically free exp.
Once you use an exp pack it disappears. So you can't "share" it.
Federation sympathizer and GM lover. NEVA GONNA CHANGE.