Notifying tasks in related roles

[Guy Knights]

I have an haproxy role that can be used for a variety of purposes (load balancing, local proxying, etc), and I need to be able to notify handlers in several other roles if a task in the haproxy role changes, based on which of those "other" roles exist on the current node. The main reason I want to do this is because the above are running in linked docker containers and if the haproxy container is restarted, sometimes the ip address of the haproxy container can change which means the linked container can't communicate with it. That being the case, can anyone tell me if there's a way to do this in Ansible?

Thanks,

Guy

[Guy Knights]

Actually, having thought about it a bit more I could rephrase my question more simply as "is there anything like Puppet's 'subscribe' relationship parameter?"