How create a construction script to add materials into a strucion blueprint

Hi guys!!!

What I am doing is a system that the viewer can change the material applied to an object on the scene. To make my life easier and others who work with me. I thought about making a blueprint where the user can set the editor that will static mesh use, change the base material of this static mesh and add one or more extra materials. All using the construction script.

The first function is the user can choose which static mesh will contain this blueprint. The second function is that user can change the materials that are applied in this static mesh. So far so good, I’ve done everything.

What I do now is that the user can choose which will be the extra materials and store them in the structure blueprint.
I thought I’d create a variable that will contain the number of extra materials. Then use this variable to create a loop and than create the options in the editor for the user to add materials.

My questions are:
How do I create these elements in the editor and then be able to keep everything in the structure blueprint.
If I have more than on of a blueprint on the scene, can create some kind of conflict.

How to do?