Reception Seating Arrangements - HELP

What is the proper way to seat guests? I was thinking something like, My family, his family, my friends, his friends, our friends, my work folks and his work folks all kind of together. However, since most of the folks he works with are African American, I don`t want it to look "segregated", but also want people to sit where they know each other. Am I making mounds out of molehills? Should I not be concerned about such appearances? His best man is also African American and will be sitting with us. Thanks if anyone can ease my mind.