Wait a minute, don't you get a listing of outbound LD calls in your monthly bill?! Can you get it via e-mail? If so you can probably find some software to massage it for the info you need.
And then you can use the PIN codes mentioned above to 'pin' the calls on the appropriate caller.
(PIN = Personal Identification Number) Typically, you dial and L/D number, then get a tone, after which you enter a 4-8 digit code. Make sure that the PIN is confirmed before the call goes through. It will take 0 time for employees to discover that any old digits of the right quantity will work and calls they don't want to be 'pinned' with will be "un-assignable".
