Gayle, You are a woman after my own heart.
I know you can make this work because you want to. You will just have to be
very diligent. I have 2 that really get into some bad fights if I have a toy in the house and then 5 more will jump into the fight and it is scary to someone who doesn't know what to do. Because I know what can happen I take precautions with the 2 of them and am always alert around them. When I feed the gang the 4 little ones go into the xpen and then I put the food down the exact way every morning and night. Every dog knows its spot and in which order I put the food down. I then stand guard while everyone eats so no one goes into the other dog territory. When I leave the house the 2 are separated and the little ones are in another room. It works for us. When neighbors come over I always point out the Sammy sometimes has issues due to his background so it is probably best that you not love on him (he doesn't want it anyways) and besides there are plenty of them around. Again, with your grandchildren you will just have to be dililgent and always be aware of what is going on or put him in his xpen. It is much better to be safe. I am sure San-Dee is a street fighter from his original home so this is what he knows. Hopefully, neutering might slow him down (it didn't mind but I can hope for you).
Good Luck and keep us update.