Will any EU PSN card work on any EU PSN account

Im trying to gift my friends some PSN digital psn fund code and I've hit a roadblock of sorts.

I'm trying to send it to 3 different friends in 3 different countries Sweden, Netherlands, and UK. I'm from the US and I've simply been buying US PSN digital codes from Amazon to instantly fund my account.

It seems I can log onto UK Amazon with my US Amazon account, but first off, I don't seem to see any digital voucher purchases and 2, will these EU codes work for all EU PSN accounts in general (Sweden, UK, & Netherlands) or do I have to individually find digital vouchers for each aforementioned country to gift to my buddies?

Thanks for the help!