Make a Supplier Registration Train Stop Mandatory (Required)

Summary:

Need to make a Supplier Registration Train Stop for Business Classification Mandatory.

Currently the screen allows hitting the "NEXT" button to bypass the stop.

Content (required):

Hope this is the right area.

We have a Supplier registration train stop process that includes a stop for Business Classification.

We're having trouble making this a mandatory "stop" . We tried to mimic the primary stop where information such as the email, business unit, DUNS, etc is required and will not let you click "NEXT" unless the data is entered.

Is there any easy method to turn on REQUIRED for the train stop? We tried making the field required but since it's a list selection it ignores the entry unless there's a way to auto drop down when the stop opens??