Sending multiple boxes by JP Post surface mail

Hi Folks,

I'm looking to send a couple of boxes to the UK as a gift, but I'm a tad confused about the labelling. I understand I need to create a label per box, but does that mean it goes through as each box being a different shipping instance with its own tracking numbers/systems? Or if I create multiple labels and ship them on the same day, do they all go under the same tracking info/shipment? Has anyone sent multiple boxes by surface mail through JP Post lately?

Thank you!