The Dunkl deformation of the Dirac operator is part of a realisation of an orthosymplectic Lie superalgebra inside the tensor product of a rational Cherednik algebra and a Clifford algebra. The Dunkl total angular momentum algebra (TAMA) occurs as the supercentraliser, or dual partner, of this Lie superalgebra. In this paper, we consider the case when the reflection group associated with the Dunkl operators is a product of two dihedral groups acting on a four-dimensional Euclidean space. We introduce a subalgebra of the total angular momentum algebra that admits a triangular decomposition and, in analogy to the celebrated theory of semisimple Lie algebras, we use this triangular subalgebra to give precise necessary conditions that a finite-dimensional irreducible representation must obey, in terms of weights. Furthermore, we construct a basis for representations of the TAMA with explicit actions. Examples of these modules occur in the kernel of the Dunkl--Dirac operator in the context of deformations of Howe dual pairs.