Enrolment rules - adding resources

Hi all

We have a simple enrollment rule that assigns a series of Courses to users in a certain Group.  I have just noticed that, after adding additional Courses to the enrollment rule resources, these are not retrospectively assigned to existing users. 

I knew that existing users do not get retroactively picked-up by enrollment rules, but hadn’t realised the same was the case for resources.

Does anybody have any advice on how best to handle this situation? Is it a case of having to manually enroll the Group to the new courses?  

Thanks!

Alan