Okay, I see it.
Pictures of Susan (the girl with red hair) and Anna (the blonde in red) are in the first chapter. Talk to Anna when she's drunk. Meanwhile, you can see Susan in the window.
After that, you can accompany Anna to her room, then you will get the opportunity to grope (no sex scene).
For Charlie (second, fourth and fifth picture), you need to get magic mushrooma in the second chapter, in the forest. After she knocks herself out, you can try to sneak into her room.