So I've been wanting to create an overhaul mod for some time (atm it's name being Aurora Imperii), and one of the key features being a total culture overhaul. Now the problem lies with British/Anglic and Dutch. For balance purposes, I wanna make dutch separate from the german culture group (along with dividing the group to high and low german) but at the same time, I want to reduce the "british" group to a germanic classification, and so could put them together with dutch to form a west germanic culture group (Anglo-Frisian language family being the main incentive) But, on another hand, I could just as well keep it separate, so I wanna know ya'lls input on this.

TLDR: should I unite the british and dutch into a single culture group, or should I keep them separate?