As long as each unmarried co-owner satisfies the two-out-of-five-year ownership and use tests, each gets to exclude up to $250,000 of their share of the gain from the sale.  

I know there's an IRS ruling about that somewhere, but I found it here with a quick search.  

https://www.nolo.com/legal-encyclopedia/how-does-the-capital-gains-tax-exclusion-apply-three-co-owne...