APT proxy for multiple repos of the same distribution

Do i need to create separate repo proxies for xenial, xenial-security and xenial-updates ?

I want to introduce a nexus proxy for a client config like

deb http://ca.ports.ubuntu.com/ubuntu-ports/ xenial main universe
deb http://ca.ports.ubuntu.com/ubuntu-ports/ xenial-security main universe
deb http://ca.ports.ubuntu.com/ubuntu-ports/ xenial-updates main universe

but i’m not sure if these are all considered 1 single distribution (xenial) or 3 by nexus for the sake of proxying