Stephanie Maxwell hopes never again to host a playdate for three preschoolers. "They're always a total disaster," says Maxwell, of Fort Wayne, IN. "My daughter Anna would invite a friend over, and then our neighbors' child would join them. Inevitably, one of the kids went home in tears."

A get-together for three can be tricky for adults; for children just beginning to develop social skills, it's nearly impossible. "By age three, they're starting to experience jealousy and rivalry," says Lisa Spiegel, codirector of the Soho Parenting Center, in New York City, "and begin to have difficulty dealing with more than one friend at a time. They just don't know how to be loyal to two different people." Consequently, two kids may pair up, leaving the third one out. And since preschoolers aren't known for their tact, they may inadvertently be cruel to the third child.

Even so, sometimes you can't avoid hosting a trio of playmates. To keep the peace:

PLAN OPEN-ENDED GAMES

While you shouldn't hover, you can guide. Suggest activities that don't require partners, such as drawing, baking, or dressing up, and make sure there are enough materials to go around.

ADD ONE MORE TO THE MIX

If possible, turn a threesome into a foursome, even if that means you're the one who joins in. Then the kids (and you) can pair off or possibly switch partners at some point, but it's unlikely that someone will be left out.

CONSIDER INDIVIDUAL TEMPERAMENTS

Some combinations will be more volatile than others, depending on the kids' personalities. "My daughter had one friend who was extremely shy," says Maura Larkin, of Philadelphia. "This playmate was able to interact one-on-one, but if a third child came over, she would withdraw completely."

MAKE IT A TEACHING EXPERIENCE

"Kids need to learn about including people," says Spiegel. "Asking your child to put herself in the position of the left-out playmate helps build empathy."

Spiegel stresses that having difficulty in groups of three is a completely human phenomenon that's simply more intense at this age. When children's social skills become more sophisticated  -- at around age 5  -- three will be less of a crowd.

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