GTM and LTM Virtual Server Service Ports

I'm trying to create a Wide IP for one of my company's applications and the application uses multiple TCP ports where each port serves a different and independent purpose. On my LTM, I have set up the Pools and the Virtual Servers for this:

 

LTM @ Data Centre A

 

• VS 1: 10.1.0.100
• Service Port: 80 (HTTP)
• VS 2: 10.1.0.100
• Service Port: 443 (HTTPS)

LTM @ Data Centre B

 

• VS 1: 10.2.0.100
• Service Port: 80 (HTTP)
• VS 2: 10.2.0.100
• Service Port: 443 (HTTPS)

What I want to do now is to create a Wide IP DNS called to load balance between these two data centres. I already have the LTMs linked up to my GTM.

 

The problem I face is that when I try to create a pool for the two IPs, I go to: Global Traffic > Pools > Pool List > Create

 

Name: sample_pool

 

Member List: <<<

 

When I try to choose a member, I notice that all the members come with Service Ports tied to them. There isn't a way to add a member without a service port and here's the issue. If I add a member from Data Centre A and a member from Data Centre B both with service port 443, doesn't this mean that if port 443 becomes unavailable at any one Data Centre, the GTM will mark the member as unavailable even if port 80 is still up?

 

I want the GTM to be able to still send traffic to Data Centre A even if 443 is down as long as 80 is up (and vice versa).