I'm on the quest Battle of Bunker Hill given by the Institute. I'd like to inform the Railroad of the Institute’s plan but every time I try, it won't let me. I used the minutemen to get access to the Institute via the teleporter. Every time I talk to Desdemona she wants me to side with the Railroad. I keep selecting side with the minutemen during our conversions but she keeps asking every time I talk to her. This is preventing me from informing her about the Battle of Bunker Hill.

Is this a bug or do I have to side with railroad over the minutemen?