Here it is another example. I have two columns A1 is ID, and B1 is ID_NB
ID ID_NB
10 4115
10 4116
10 4117
10 4118
10 4125
10 4126
10 4127
11 4110
11 4111
11 4112
11 4113
11 4125
11 4126
11 4127
15 4150
15 4151
15 4152
15 4153

What I need is to group numbers from ID_NB only if them are consecutive, based on ID, extracting all the consecutive intervals only and the afferent ID.
For the above list, desired result would be:
ID Small Big
10 4115 4118
10 4125 4127
11 4110 4113
11 4125 4127
15 4150 4153

I don't even know if it's posible to do it in excel, i hope that I explained myself better this time.
Thank you once again for you patience.