Any ideas?

I've had numerous email accounts over the years and after awhile they just get rammed with junk. I have three at the moment, two of which have about 5,000 unread emails between them

The other account I opened up last year was solely meant for my mahal and friends although I might have given it to my bank and maybe a company I was in regular contact with. Now I'm starting to get all the pap into my inbox and some of it's the dodgy emails that want my bank details.

Is there an option to only allow emails from people you know with the rest getting filtered out?