How to merge certain pdf files wich contains a specific substring

Hello

I am trying to select pdf files wich contains a specific substring and merge those pdf files

i am able to find the files in a specific directory wich contains the substring.
i can merge all the files in that directory.

But i do not know how to merge the files wich contains the substring.

Uipath binders maken facturen.xaml (17.7 KB)