That signal is bugged on 0.52. You can go though #6 but sometimes it won't give you a new signal, in your case you havent reached that point yet so idk if you will have that issue. If you do join the DC and I can send you a save file.
But to get though it to see if its bugged What you need to do is convince all the girls to join you by using t he portal in your room, then go to the handling room to "give" then their rooms. Then go to the meeting room once you have done that.