Setting up US account + PS Plus (New Zealander)

Hey guys!

I've been thinking about setting up a US PSN account to reap the sweet prices that the US gets on their PSN store. I've seen a tutorial explaining the basics of doing this (Amazon giftcards for store credit, setting the US account as primary account so I can play the games while on my NZ account).

I'm already an existing NZ PSN user, with an active monthly PS Plus subscription.

Is there a way I can share the PS plus status with the US account (once that's created)? Or do I need to buy a separate PS plus subscription for that? If so, should I cancel the sub with NZ and just have it going for the US account?

I tried googling this, but received mixed answers.

Thanks guys