Boarding order is as follows: 1st on are the special needs boarding, second are a boarding passes A1-A15 (business select) then after that A15-30, next A31-60. After the A's they call for the families with children 4 or under, and then they board the B's and finally the C's..
I generally buy the early bird check in for my trip home so I do not have to worry about getting a boarding pass at the 24 hour mark.
If you do not buy the early bird check in, be on line at your 24 hour mark to get your boarding passes. Even if you have a low number B you should all still be able to sit together.
If you want to buy the early bird check in you can go online to purchase even if you've already booked your flight. Go to the SW home page and scroll down under SW products is a link to add the EBC.
