Best way to set up Course1 as a pre-requisite to Course2

Summary:

We have two management development workshops which need to be completed in order. We don't mind them booking spaces on both at the same time, but they must attend Course 1 before they attend Course 2.

Content (required):

The only solution I've come up with so far is to set Course2 as no access and have an access group consisting of people who have completed course1.

Is there any other way of managing it? I prefer the actual prerequisite functionality, as it gives a nice clear message on the course page.

Version (include the version you are using, if applicable):

21D