I would like to do taxes for 4 family member with the Premier edition and take advantage of the "LIVE" help for ALL of the 4 returns. What is the best way to purchase?

Is it possible to use the download PC version and THEN upgrade for LIVE to get help with any (or all) of the 5 returns? I just don't want to be caught after the fact.

OR do they make me pay for 4 separate LIVE versions? That would seem too costly...