Merge award reservation with cash reservation?
 

I am able to find at most 3 economy award seats for my desired ANA route (guessing that's all they release), but I need 4 seats (2 adults 2 children). I'm wondering if I would run into any problems if I booked 3 seats via awards and 1 seat in cash? Would I be able to call to get them linked on the same reservation? I would like to avoid unfortunate situations like being split onto different flights if one is canceled.