Hello Aksel. The problem related with how you handle courses. Portions should not be used for this purpose. You can use Order State feature for that. Think it like updating state of an order as Mains, Entree or Dessert. You can get basic information about Order states from this link What does State mean?. Also [New 4.1.14] Limiting Payments by Payment Type tutorial has an example to create a button for updating individual order states. When you mark orders with order states you can group print outs as described here Grouping on Ticket Printer Template [SambaPOS V3].
For a complete sample you can also try John’s Kitchen Monitor sample. It supports courses.