these servers need to be accessed from the outside, right? If so, I assume you have a static NAT for one server (public to private NAT). The ASA doesn't allow to have two different static NAT sharing the same outside IP going to two different internal IPs. You can do port-forwarding which means you can use the same external IP, translate different ports to different IPs.
I assume you want:
outside public IP: x.x.x.x
private IP A: y.y.y.y
private IP B: z.z.z.z
static (inside,outside) x.x.x.x y.y.y.y
static (inside,outside) x.x.x.x z.z.z.z
The above is not allowed. You can do the following:
static (inside,outside) tcp x.x.x.x 80 y.y.y.y 80
static (inside,outside) tcp x.x.x.x 8080 z.z.z.z 80
The above shows port redirection using the same outside IP, two different ports redirected to two different internal IPs with the same destination port.
I hope this clears your question.
