Nullifying lease clause for potential tenant

[Ian MacDougall]

What's up BP,

I'm about to rent out my first property (house hack) in central VA to tenants that aren't friends - as in, I went through the full screening process and application. I have a couple that look to be a great fit, and I approved them today after they passed all background/income/credit checks. They're looking to rent for at least a year. However, upon asking their move-in date, the wife had a question about nullifying the lease. They're selling their current residence before moving into my rental, and plan to close in the middle of October. Based on a similar experience selling a house a few years ago, she's worried if the buyer pulls out before closing then they would be stuck with their mortgage as well as a lease with me.

So, is it possible to structure my lease with a nullification clause that if their sale falls through before close, then they can break the lease? If so, how should I go about including that clause, or is it worth waiting until after their closing date (couple weeks from now) for them to sign the lease?

I know this is likely a question for a RE attorney (don't worry I won't sue for any advice you give :) ) especially if I need them to add the clause, but I figured I'd ask for anyone's thoughts if they had experience with this.

Thanks in advance!

-Ian