You can (agent knowledge provided) have both an award and paid booking on the same PNR provided all passengers are booked in the same booking code on each flight. If different booking codes are involved, then you do have to have separate PNRs.
For example, you both are booked in T SFO-JFK on an award, but then pay and are in G JFK-LHR, it can theoretically be done. But if only one you books in T on an award and the other person pays an H fare, the system will require a second PNR.