Identifing rows based on multiple form sources

We have a form which is sent to customers to register their commercial contact details. The customer doesn't always know which product they are receiving so this is added to a sheet column after population. However, a new row triggers notifications to various internal stakeholders and they receive this notification before the product column has been populated. Whilst the notification workflow could include a step where the notification is not sent until the additional column is populated, it would be great it this column could auto populate based on the form origins.

The ideal solution would be for each sales department to have their own form populating the same sheet but how can we automatically identify which rows are populated by which form?

Thanks