Mrs. S escorts Sarah to the hideout where she is hiding Kira in episode 2x02 "Governed by Sound Reason and True Religion".
Source: Orphan Black — Wikia
Cosima wakes up in the middle of a strange and isolated Neolution village on the island in episode 5x01 "The Few Who Dare". Cosima talks to Aisha about her illness and then is brought up to the main house to meet with P.T. Westmoreland in episode 5x02 "Clutch of Greed". Ira arrives and talks with Susan while Cosima investigates the mysterious something in the woods in episode 5x04 "Let the Children and Childbearers Toil". Appears in 3 more episodes.
Pilar keeps Christie, Alak, and their child hostage in a secluded house in episode #301 "The World We Seize".