https://helpx.adobe.com/experience-manager/kb/HowToDefineComponentListDynamically.html
The instructions in that Knowledge Base article do not seem to work with AEM 5.6.1. I have raised DayCare ticket #80287 about that.
Is there a way to achieve the same in 5.6.1? Can the allowed components for a parsys be dynamically defined, so instead of using a design to specify the allowed components, the components themselves can control what may be placed in them?