madness.jsx

return (
  <MultiChildComponent>
    <ChildNode key="child1">
      <span>Yo</span>
    </ChildNode>
    <ChildNode key="child2">
      <span>Dawg</span>
    </ChildNode>
  </MultiChildComponent>
);

class MultiChildComponent extends React.Component {
  getNamedChild(key) {
    // hunt through this.props.children, looking for ChildNodes, and then matching by key
    // ...
  }
 
  render() { 
    return (
      <div>
        <div>
          {this.getNamedChild("child1")}
        </div>
        <div>
          {this.getNamedChild("child2")}
        </div>
      </div>
    );
  }
};