Incoming Challenge: Is it possible to stay friends with an EX?

I have been with my boyfriend for 5 years. We were really close friends before we started being together and one of the main reasons for me to prolong the relationship was that I didn’t want to lose my best friend.

Now we’re done as a couple (it was a common decision) and we would both like to remain "being friends" but I am not sure if that is even possible? We share the same awesome group of friends and us not being able to continue the friendship, would mean that the group has to split in one way or another. We’d like to give it a shot, what would be the best way to handle that situation?