A Lie for a lie

When is it a good time to lie? Or better yet is there ever a good or proper time to lie? This is a question that is routinely used in one of the few organizations that I am priveiaged to be apart and hold an position in. Anyway to get on with the story and my point, I was faced with this very problem after a certain truth had been revealed to me. How? It doesn't matter because in exploring this topic I came to the conclusion that truth or the truth is the right of all that the certain truth might effect. In the pursuit for a deeper understanding of the truth I would began to reveal my knowledge of the truth to one of it's primary sources. My attempts for a deeper understanding I was met with confusion in the form of questions and anger at the knowledge that I had thus far displayed. As a reaction I prepared my defense by ceasing the divolging of my limited known truth, in short I LIED. I honestly opened up to them in hopes that the same attitude & behavior might be returned, but lied as soon as I felt betrayed. The conversation then took a turn for the worse after they tried to disvalue the truth, told me that I had no right knowing these facts and that the truth can/will be hidden. After studying I came out with the phrase "an eye for an eye" Exodus 21:23–27 which made me feel secure in that I had made the right decision by protecting my knowledge, but was later brought to the light with Galatians 6:7. This simply states that a person reaps what they sow & prompted me to ask for forgiveness from two individuals that I had wronged in the past. Was this the fruits of a past misdeed commited by myself? NO. The people that I had asked for forgiveness had forgiven me years ago due to the fact that I asked years ago. So the question still stands, should I come clean about what I know and to what extend? As simple as this sounds I need help. This truth does or would effect several individuals if revealed,so at what point does this choice become an obiligation?