(This has probably been addressed somewhere, but I couldn't find it in the stickies, search is down and it's probably the work of fifteen seconds for a knowledgeable person to answer it.)

I'm considering a DONE5 this summer. I'd leave Boston for Australia in late May, continue on to London, hang out there for a couple of months, go to Africa in August and return home. So far, so good.

Problem is, I can't just hang out in London, or in Europe, for 2+ months.

So I'd like to buy a ticket LHR-BOS-LHR or some such to get me home and back between early June and early August. And I'd like to do it on AA, or as a minimum on a oneWorld airline, for the miles and such.

Can I do this without screwing up the ONE by returning to my point of origin? Does it help to return to a different airport, say, PVD? Or a different country, in this case Canada (Montreal)?