Someone

notifications:
  groupa:
    email:
      to: me@here.com
      template: sometemplate
  default:
    im:
      network: jabber

feeds:
  feeda:
    ...
  feedb:
    ...
  feedc:
    notifications:
      prowl:
        to: whatever
        template: othertemplate
  feedd:
    notifications: groupa


-------------- Or, in it's simplest form:

notifications:
  e-mail:
    to: test@example.com

feeds:
  feeda:
    ...