Apply to each string variable

I'm trying to compose an email address to multiple people -- in the greetings, I'd like it to look like below, with each name separated by a comma but the last one should say 'and'

Probably need to identify how many recipients...
If only one recipient: 
FirstLastName1,

If two recipients:
FirstLastName1 and FirstLastName2,

If more than two:
FirstLastName1, FirstLastName2, FirstLastName3, and FirstLastName4

Is this possible?