In ballistic/chaotic quantum dots the single-particle states are controlled by Random Matrix Theory below the Thouless scale. The three pure Random Matrix ensembles correspond to dots without an orbital B field and no spin- orbit coupling (Orthogonal), dots without an orbital field and with spin-orbit coupling (Symplectic), and dots with an orbital field (Unitary). At weak coupling, the low-energy physics is described by the Universal Hamiltonian. We will be concerned with interacting electrons in a dot in a crossover between two RMT ensembles, such as the Orthogonal and the Unitary, and we will show that in the crossover, special RMT correlations develop and the states become strongly correlated in the electronic sense. We will conclude with a description of new universal interacting crossover regimes.