I got all the Values in the request on the server side . Which i used for the creation of the XML tags which is combination of the 2 child tags HL and LL .
After that as my product provides the sorting functionality , so used it and then finally used the below condition if whole structure is valid or not on the server side.
1)First LL - > Should be equal to some start value. So that we will check start
2)Last HL--> Should be equal to some end value .
3)Most important question --> Current LL - Previous HL = 1 this condition should be applied . If not following then validation failed.