The only methods Logic offers for this are:
1) use the Pitch & Time Machine (performed in the sample editor, and it's a destructive operation so be sure to create backups first)
2) convert them to Apple Loops, at which point you can change their pitch by adjusting the key
Another option:
3) Slap a Pitch Shifter II Effect plugin on the track. Set to 100% wet and adjust pitch shift to taste.
If you need the audio region permanently pitched bounce the region in place.
