How do I add controller support for diagnol movement in UI

I am trying to create my own variance of a radial wheel UI for my project. What I want for this menu is that when the player has this menu pulled up the player can press up, down, left, right, or diagonal(NE,NW,SE,SW) and it will highlight the button that matches one of those directions. My problem is that I cannot get my UI to recognize a diagonal input from my controller. Does anyone have an idea on how to do this? I am aware that UE4 has a marketplace purchasable that does all this, but I want to make my own and I am really close this diagonal piece is the last part I am missing.