Suggestions for getting 2 households to initially interact without playing both?

MCCC also has a "teleport any sim on top of my active sim" function no mailbox required. I usually use it for posing in places where I cannot use the teleporter statue.

Come to think of it, if MCCC is too big a commitment, the smaller mod Teleport any sim might be what you need. It works by placing a teleporter statue on a lot, then clicking on it and summoning any sim (including hidden households). When they arrive the statue conveniently gets consumed/deleted.

It's the third or fourth mod here: http://sims4studio.com/thread/2617/andrews-studio?page=1