We detect a certain pattern of behavior of separability probabilities p(rA,rB) for two-qubit systems endowed with Hilbert–Schmidt (HS), and more generally, random induced measures, where rA and rB are the Bloch radii (0≤rA,rB≤1) of the qubit reduced states (A,B). We observe a relative repulsion of radii effect, that is p(rA,rA)<p(rA,1−rA), except for rather narrow “crossover” intervals [˜rA,12]. Among the seven specific cases we study are, firstly, the “toy” seven-dimensional X-states model and, then, the fifteen-dimensional two-qubit states obtained by tracing over the pure states in 4×K-dimensions, for K=3,4,5, with K=4 corresponding to HS (flat/Euclidean) measure. We also examine the real (two-rebit) K=4, the X-states K=5, and Bures (minimal monotone)–for which no nontrivial crossover behavior is observed–instances. In the two X-states cases, we derive analytical results; for K=3,4, we propose formulas that well-fit our numerical results; and for the other scenarios, rely presently upon large numerical analyses. The separability probability crossover regions found expand in length (lower ˜rA) as K increases. This report continues our efforts [P. B. Slater, arXiv:1506.08739] to extend the recent work of [S. Milz and W. T. Strunz, J. Phys. A48 (2015) 035306.] from a univariate (rA) framework — in which they found separability probabilities to hold constant with rA — to a bivariate (rA,rB) one. We also analyze the two-qutrit and qubit–qutrit counterparts reported in Quantum Inform. Process. 15 (2016) 3745 in this context, and study two-qubit separability probabilities of the form p(rA,12). A physics.stack.exchange link to a contribution by Mark Fischler addressing, in considerable detail, the construction of suitable bivariate distributions is indicated at the end of the paper.