Toddlers have a great deal of difficulty sharing materials from a common pile. Give each child his or her own pile. Make it clear that this pile belongs to Jimmy and that pile belongs to Terry. This will help you avoid arguments. Many conflicts can also be avoided by limiting the number of children playing in any one area.
Fewer children make for fewer social problems and, thus, fewer conflicts.
Also, make sure toddlers have plenty of space. Because toddlers are small, it is commonly assumed that they need less space. Toddlers actually require more space than older children because they don't respect the space needs of other children yet. Furthermore, because they do not have good control over their bodies, they may accidentally move into another's space. If you provide several feet of space between children, this is less likely to occur.