Programmatically arranging contents in aem 6.4

Hello everyone. I'm new in working with aem. I'm using aem 6.4. My task is to programmatically sort the order of the contents of a cq:project in aem depending on the content of a json file. The content of the json file should be set as the initial child instead of the children sorted by their creation date.

This is the current structure of my cq:page. If the child2 is the one indicated in the json file, it should be the first one to be displayed. The content of the json file is just the name of one child so even though there are 10 children, the content of the json file should always be the first one in the list.

I've spent hours researching on how I can implement this although I still can't find any solution. Any insights on how should I create this? Thanks!