Hey! I know when my mom got remarried she and my stepdad presented us w/ family medalions. It is a pendant of sorts with three interlocking circles. I am not sure where you can get them, but I am sure anything given to your kids on the special day will mean a lot to them (and the two of you know your kids better than I do). As for including them in the ceremony, I like the idea Rachael had of the oldest walking you down the aisle, or maybe even walking down with the girls? He and the oldest daughter could walk on either side of your little one and help her down the aisle, then she could go sit with the grandparents. Just a few ideas. :-)