An uncoupled CFD-DSMC technique is developed and applied to provide solutions for continuum jets interacting with rarefield external flows. The technique is based on a correlation of the appropriate Bird breakdown parameter for a transitional-rarefield condition that defines a surface within which the continuum solution is unaffected by the external flow-jet interaction. The method is applied to two problems to assess and demonstrate its validity: one of a jet interaction in the transitional-rarefied flow regime and the other in the moderately rarefield regime. Results show that the appropriate Bird breakdown surface for uncoupling the continuum and non-continuum solutions is a function of a non-dimensional parameter relating the momentum flux and collisionality between the two interacting flows.