If you're arriving at BOS on an international flight and clearing customs at Logan, then no, you'll be dumped out landside in Terminal E. With the new post-security terminal connections, provided you have your onward boarding pass (i.e., don't need to check in with your next airline in Terminal B) you could certainly choose to clear security at Terminal E - just go back upstairs. However, keep in mind that once you leave the lounge in E it's a good 15+ minute walk to B. Also depends on who you're connecting to in B - you'll reach WN and AS first in B (coming from C), then UA, and AA and AC are all the way around...more like 20+ minutes to reach AA or AC.