Exchange 2013 CAS and DAG Roles

In our current environment we are running Exchange 2013 with servers running separate roles CAS and DAG servers. The DAGS are clustered together for fail over. We are told in order to implement exchange online hybrid model we need to have a server that has both roles CAS and DAG installed on it to communicate with the cloud. 

If i spin up a new server and put both roles on it CAS and DAG will it work in my current environment?

Thanks