Since you're trading both for the same purpose, selling for Keys / Promos, and the only difference is a discount for the bundle, I don't see why you can't just open only one trade with both Unusuals on the left side and a Bud (and a Key and Bill's ...) on the right side.
The different prices and the discount can be set in the trade notes.

I really don't see any advantage for you by listing multiple times either. It won't increase your chances to sell your unusuals, imho.
And I have no doubt that people will offer an a single unusual in a bundle trade anyway. And then you would have to manage you C/O across trades (assuming you also take offers and your prices are a B/O)

Thanks for the answers guys

@samhudson333 :
The third trade is for selling them as a set only but if a person makes an offer on only one of the items on the third trade what should I do? Should I tell him to go to the other trade that I opened for that one item?

@Uranium235 :
I wanted to make a third trade because alot of people get confused when they see a trade like the third trade and they think that you are selling the items only as a set.

Alright, thanks :D