Daisy Chain data sqls extraction

[vkunta]

I have situation where table contains data where subset of a data can be linked.
Ex: Col1 COL2
1 2
1 3
3 4
5 8
8 9
Some kind of Daisy Chain situation.

I need sql which will update third column where all rows linked.
Ex:
COL1 COL2 Group_ID
1 2 1
1 3 1
3 4 1
5 8 2
8 9 2


Can anybody have any solutions using with or with out temp tables?