The zones are physically separated, so you cannot simply wander from one lounge to another. You also won't be able to get into the transborder zone without clearing US immigration, so that's essentially a no-go zone.

It might be possible to use your Mexican BP to get you through the domestic security and into that zone (and from there, into the domestic lounge) ... I don't know how strict the security folk would be about enforcing access to only domestic travellers.

If you were able to get in, then after you left the lounge you'd need to following the directions for domestic to international connections (here) to get to your actual departure gate.