No, this isn't possible. The annotations work by triggering the creation of a proxy around the class instance you're calling. This is most convenient for Grails services since they're automatically registered as Spring beans, so the annotations are detected and they get proxied. You make the method call on the proxy, and it does the ACL check and only invokes the real method if access is allowed.
But with static methods, or dynamic Groovy methods, or methods in classes that aren't registered as Spring beans, this proxying can't happen. For this example, create an annotated service method. You can still leave all of the code in the domain class, or even use dynamic finders, but the important thing is that the access is done through the proxied service. Once that check happens, you can implement the logic however and wherever you want.