Is that another way of saying San sou

The characters for San Soo are the same as "San Shou," but Kung Fu San Soo is unrelated to San Shou/Chinese Kickboxing.

so....is it's own Kung fu style that resembles one of the three internals

Kung Fu San Soo doesn't resemble any of the Internal styles.

Kung Fu San Soo is a Southern Chinese martial art with ties to Choy Lay Fut and related systems, with the training placing a heavy emphasis on self-defense techniques.