You can achieve that with Access Rules. But first simplify your domain model
if wenslijst_tussentabel, leverancier_product_tussentabel and bestelling_heeft_producten have no attributes they can be replaced with a reference set association
Add an Bestelregel entity with at least amount and unit
After that add an access rule to bestelling
for the Role Supplier
This means that only accounts related to levancier can see the lines of the order which they supply.
Make a rule for a client/klant that they can only see their orders/bestellingen.
My answer is quite short, please read the documentation about access rules.