Not a problem at all, feel free to use them. Please give me a sign once you've done that, I would love to see it.
To provide some context, I mostly make decks out of cards from one set and restrict myself to use 4 of each common, 2 of each uncommon and 1 of each rare (no mythics). In a way they resemble extremely good draft decks. Most of the times they play around with one central theme or one central keyword.