Groovy rule to add a new row

Summary:

Groovy rule to add a new row in the form

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Hi all,

I've created a form that works a bit like a journal where a user can select the cost centre and account to transfer costs out of and in another line can put the cost centre and account to transfer to. It could be that a 10k out of a cost centre can go as multiple 2k's to a number of different cost centres. For this I need to allow the user to create additional rows on the form.

I've been trying to look at ways to code this in a business rule, but can't seem to get anything to work. I suspect this will need to be a groovy script? Any advice or any examples anyone's got would be really appreciated.