Need advice! Wedding Gift

If someone that you work with, not someone in your office but more like a business contact, buys you a wedding present off your registry, and they just got married themselves, would you buy them a gift off their registry also? Or would this look like you're just buying them a gift because they bought you a gift? I feel bad, someone bought a gift for us, and they just got married a few months back and their registry is pretty much wiped clean except for a few things.

What would you do?