How to compare Requested Ship Date of different Iines?

Summary:

Line with greatest Request Ship Date to be defaulted for all the lines.

we are using OM extension to populated RSD on order lines.

Content (required):

We are creating a ship set for the order, but if one line in the ship set contains different RSD, order is not getting submitted.

So we need to change the RSD for all the lines with the line having greater RSD.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):