Tetraquarks are 4 particle quark states since 3^4 = 3×3×3×3 = 81. In trying to organize the 6 known quarks, charm, truth, beauty, up, down, and strange in the weight diagram of SU(3), does the description of and the properties of the X(3872), X(4140), X(5568), X(6900) exotic Hadron tetraquarks fit into the (2,2) + (2,2) + (2,2) = 27 + 27 + 27 = 81 highest weight representation of SU(3) and the (2,2) highest weight representation of SU(3) be a basis from which one could make predictions about the existence of undiscovered tetraquarks?
See B. Hall, Lie Groups, Lie Algebras and Representations, p 151 for a description of the (2,2) highest weight diagram.