Order By

Hi

I have field Order No data type is string . Data is like this

ABC/MHL/PUR/09-10/1
ABC/MHL/PUR/09-10/2
ABC/MHL/PUR/10-11/1
ABC/MHL/PUR/10-11/2

09-10 & 10-11 are financial year.

I want to display data order by financial year + value after financial year /.

Thanks