How to delete a color in an object reflection?

Hi all!

First of all, you need to know that I am a noob with Unreal Editor :stuck_out_tongue:

Here it is my issque :
In Unreal Editor, I have created a virtual set with greenscreen. In front of it, I can set some 3D objects with reflection. I would like that these objects do not reflect the greenscreen but can reflect lights and other elements. Please find an overview attached.

I tried some solution but I did not find out.

Thank you for your help!