Limit Itemization in Expenses

We have a requirement to limit expenses so that per expense item created, the user can only itemise once.

For example, we have "Travel - UK" as an expense type, we require the end user to only select one itemisation for that so "Trains" and then attach one receipt and continue on to create a new item under "Travel - UK" for the claim for "Buses" for example as opposed to selecting "Travel - UK" and then itemising several lines under this with multiple receipts attached to the one item type.

Are we able to prevent multiple itemisation so they can only itemise once per expense type?