Is there a way to use same IP for different host groups?

This has nothing to do with groups of hosts, actually, but everything
to do with hosts.

Example:

alias1 ansible_ssh_host=portal ansible_ssh_port=1000
alias2 ansible_ssh_host=portal ansible_ssh_port=1001

and can also be written as:

alias1:1000 ansible_ssh_host=portal
alias2:1001 ansible_ssh_host=portal