Can you select the same key assignment twice on the mouse and keyboard in Fortnite, if so how?

In Fortnite, I would like to set the mouse wheel down to the second assignment on the keyboard and mouse for edit building and turn the mouse wheel down to the second assignment when changing back

I'm looking forward to your reply

Do you mean this?

For me, if I choose one, the other goes away and I can't prove it twice

Wait a moment i start fn for a moment

So for me it's normal like in the video