Detecting objects within a radius of eachother

I am trying to make a crafting system similar to that of the forest and stranded deep. The idea is as follows: lets say you have a stick, vine, and rock on the floor. If I click a button, lets say the “f” key, a crafting type GUI will show up and I can combine the rock and vine or rock and stick or stick and vine or all three, and of course if there are more items they will also show; however, they need to be in a specific radius of each other and if the player looks at them maybe theyll shine or something to show you can jump into this specific GUI. My issue as of right now is that I’m not sure how to do the idea of selecting multiple items in a radius when the player looks at them.