If I have data laid out as follows

Col1 Col2 Col3 Col4
Name1 111 tyr uuu
Name1 222 tyr uuu
Name1 333 tyr uuu
Name2 111 tyr uuu
Name2 222 tyr uuu
Name3 111 tyr uuu
Name4 111 tyr uuu
Name4 222 tyr uuu

How can I use a formula in a new column to get the
following output

Col1 Col2 Col3 Col4 Col5
1 Name1 111 tyr uuu
1 Name1 222 tyr uuu
1 Name1 333 tyr uuu
2 Name2 111 tyr uuu
2 Name2 222 tyr uuu
3 Name3 111 tyr uuu
4 Name4 111 tyr uuu
4 Name4 222 tyr uuu

the name in the above column 2 will always be the same
they will always be in consecutive rows as I will sort
first.

I dont know if this is possible but if it is it will save
me a lot of time :-

Andrew