I recently applied for a position in three separate divisions of the same company (goverment organization, actually). The organization is big enough that the respective managers would not know each other. In my cover letter for each I mentioned that I had sent resumes to the other divisions as well. Division A got back to me first and I went in for an interview. Things went well, and we decided to move forward with the hiring process, which can take up to three months in the government. I told the manager that I would still be investigating other opportunities until I had a formal offer in hand. He said he understood and asked that I let him know if I found something else.
The following week I was contacted by Division B and went in for an interview exactly two weeks after the first. This also went very well, and the following week they called and expressed interest in moving forward with the hiring process. I was clear with Division B that I had already interviewed with Division A and that they were working towards getting an offer for me as well.
Now, 3.5 weeks after the first interview and 1.5 weeks after the second, I get an email from manager A saying that HR has notified him that another group is also pursuing hiring me. He wanted to know if I had interviewed with them and if I had a preference. I replied and said that I was leaning towards Division B, but I hadn't wanted to say anything until I had formal offers in hand.
This all left me feeling like I had not been fair and upfront with manager A, especially considering there was a good chance he was going to find out on his own anyway. How should I have proceeded? Should I have let the manager from Division A know as soon as I had the interview, or was I right to try to wait until I received a formal offer? Would it have been better that he heard from me and not HR?
UPDATE:
Manager A responded and said that the organization will only give an official offer from one division, so I unfortunately do have to make a decision before an offer is in hand. I don't think this affects the answers to the question, but it does add an interesting complication to the whole scenario.