bridge_mappings = physnet1:br-ex,physnet2:br-ex2

I figure out that in standard configuration ansible playbook create br-ex and add

the interface with variable "neutron_external_interface" under br-ex.

What can I do if I need to do if I wand more than one bridge ?

How kolla ansible playbook can help in this case ?

I could use multiple bridges in /etc/kolla/config neutron configuration files, but I do not know how ansible playbook can do the job.

because I do not see any variable can help me in /etc/kolla/globals.yml 
Thanks

Ignazio