Is there a way to take three bytes, A, B, and C, that all have values between 0 and 255, and turn them into two bytes, with the values between 0 and 255, while maintaining the ability to recall numbers A, B, and C.

For example, if I where to have Bytes A, B, and C, and I where to apply a formula to them, I would get D and E. If I told you D and E, could you figure out A, B, and C, given the formula?

I need the formula, that can turn 3 bytes, into 2 bytes, and then, back to 3 bytes. Any help would be appreciated.