Probably could mod where you have say 9 months after war with the UK to control Narvik or access to Sweden is cut for 4 months. But it would have to be a mod most likely. PDS doesn't like railroading people into having to do stuff in HOI4 and this might be taking realism too far for them.
You could write it up as a suggestion in the sub forum, they will take a look at the idea.
Yes I was thinking of a mod as well, I don't think such a clumsy solution could be in the base game. I've done some of the Scandinavian mods on the workshop, working on Norway right now so if there are any good ideas on the implementation of this I'd be happy for more ideas.