Express each of X, Y and Z in terms of a,b,c,p,q and r so that the equation given below becomes an identity.

(a³+b³+c³ - 3abc)(p³+q³+r³ - 3pqr) = X³+Y³+Z³ - 3XYZ

Note: Disregard any permutations. For example, if (X, Y, Z) = (α, β, γ), then (X, Y, Z) = (β, γ, α) is invalid.