Show category name only once @ home

Hi there, I was wondering if there’s a way to show category name only once if there’s a sequence of two or more posts in the same category @ home.

Example
I want to turn this:

• Post 1 (category A)
• Post 2 (category A)
• Post 3 (category A)
• Post 4 (category B)
• Post 5 (category B)

into this:

• Post 1 (category A)
• Post 2
• Post 3
• Post 4 (category B)
• Post 5

does anyone know how to do it?
thanks!!