Ideas for communicate N systems that uses ROS. (Example inside)

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Hi, this is the situation:

let supose we all live in a small town where everyone has an autonomous car using ROS.. :D

Now, we want to enable V2X communication in our vehicles (vehicle-to-vehicle and vehicle-to-infrastructure) in order to stablish an intelligent transportation system, ITS.

questions are:

¿How to communicate N ROS systems between themselves in a intermitent wireless network?
¿How to communicate ROS systems through a Non-ROS System at Infrastructure*?

I know this is a very wide question, but I want to know if there is a proposed architecture for systems like this.

Thanks.

EDIT:

Non-ROS system could be, for example, a web server for traffic info or a intersection manager, etc.