Of course they can. In fact, you don't even need to change their roles.
Both can easily be Physical sweepers. Yache SD Chomp and Dragon Dance Salamence lure out each other's counters and significantly weaken them, allowing the other to sweep unharmed.
In fact, triple dragon is viable provided you find a decent core to support it.
I remember I ran Yache SD Chomp, Life Orb DD Salamence and Haban Berry DD Dragonite on a team with Suicune, Celebi and Scarf Heatran, and even though it was just "for fun" it still did phenomenally well on the official server's ladder in like February.