Running validation multiple times on single request

[eluser]feel[/eluser]
I would like to reuse the ruleset 'item/add' that I already use for my form. Also, the ruleset is quite large and it would take a lot of code to create all rules for a single row.

Also, I don't understand how setting rules manually at each iteration would be different then invoking dynamically specified ruleset (like I currently do)? How would this solve my problem with error messages being persisted between iterations?