Miles Plus Money And Connecting Flight Question

Hi
I'm wishing to purchase 3 Upper Class flights with miles and money (very good price to San Francisco), but need a connecting flight from Edinburgh.
Is it possible firstly to purchase the cheaper flights with Virgin and pay the full price for the connecting flights with Virgin also, so I can get the full luggage allowance and transfer of bags?
Cheers in advance.
I'm wishing to purchase 3 Upper Class flights with miles and money (very good price to San Francisco), but need a connecting flight from Edinburgh.
Is it possible firstly to purchase the cheaper flights with Virgin and pay the full price for the connecting flights with Virgin also, so I can get the full luggage allowance and transfer of bags?
Cheers in advance.