I just solved by saving the keys as a string in the objects, and when a key is pressed I redirect the key to the specific object and get the “Get Display Name” and perform a String-Comparsion. Work’s so I am happy with it. 
Thanks for your answer anyways
But no, hasn’t to be in blueprints. I only do certain stuff in BP, most things in C++. If you have a cleaner solution let me know about it