I put my hand on his to acknowledge him and let him know I'll get to him in just a minute.
And then I tell my friend to excuse me as I turn my attention to my little one, who is then beside himself with excitement to talk to me. (I'm in high demand around here.)
And then someone else runs up and puts her hand on me while Daniel's still talking. I feel so loved. And look how patiently my friend waits to have my attention again!
Everyone gets the attention they want and there's no interrupting.