So now, do you think that some damage may happen to the board if i try to divide them?
Do you have any suggestion on how to act?
Wow that is quite the defect! As far as permanent damage, it is possible if at any time both pins 5 and 6 were programmed to be output pins and then one set high and one set low. That would cause a short circuit between the pins and would damage one or both pins.
The fix shouldn't be too hard, but will require a soldering iron to remove most of the solder causing the bridge and then something sharp like an exacto knife to make a cut between the pins.