<font face="Verdana, Arial, Helvetica, sans-serif" size="2">no because aa offers that qf 107 as an option for the first leg of a lax-jfk-lhr flight. i wanted to know if i could book it with out continuing onto lhr?</font>
The answer is you can't book QF107 LAX-JFK, or any codeshare of that flight for LAX-JFK. You can book AA7365 LAX-JFK (the AA codeshare of QF107) as part of another AA intinerary (eg LAX-LHR), but not by itself.
Hope this is a bit clearer!