How to group conflict events from my table [Resolved]

Hi all

I have a event table having id,name,fromdate and to to date i want to group conflicting evnts and drop event those havnt any conflict.i want output as.the dates with no conflicts are not listed in the output.I want to identify each group thats why added groupnohow to group like this in sql server

id name fromdate todate groupno
1 a1 1/1/2013 1/2/2013 1
2 a2 1/1/2013 1/2/2013 1
3 a3 5/1/2013 10/1/2013 2
4 a4 6/1/2013 8/1/2013 2
5 25 7/1/2013 7/1/2013 2

Thanks in Advance
Amrritha

[Resolved]