It depends on the type of membership agreement you have with the other collecting society. If you are registered with ASCAP, BMI or SESAC you can sign up with Soundreef and our automated process will allow you to assign the royalty collection for certain songs in a given territory to us for the type of right you select.
If you are registered with another collecting society you will have to opt out with them for live rights entirely, this blog post explains what that entails and how to go about it.