Question in construction script

Hello, In Construction Script… Let’s say I have an object with only one Material ID (Single Element)
The object in my case is a closet, I want to create multiple “dynamic material instances”
Two dynamic materials who have the same “Element Index” which is 0. And different “Sources Material” as Variables…
My problem is i’m not really sure about the way I should do it… as in the picture, only one Material will apply to the object… because they both have the same “Element Index” …
How can I make this work? maybe a check box to apply a specific material or something to allow me have more than one option to apply material of an object… any ideas?

https://scontent-cdg2-1.xx.fbcdn.net/hphotos-xat1/t31.0-8/11536424_798544166930558_3475429316275083139_o.jpg

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xpa1/v/t1.0-9/11048763_798544090263899_2969046980407448284_n.jpg?oh=5083faa9dc8f61caf1d07fe553ba65b4&oe=5623D5B2&gda=1445591050_d6aca78311f85a1cc15392264192e0d6

One of the good people on a facebook UE4 group solved this for me

https://scontent-cdg2-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/10286961_403813226471582_2162428025157363741_o.jpg