Separating a certain middle component of isotopes from a multicomponent isotopic mixture is much more difficult than separating the two end isotope components. Numerical investigation revealed that by controlling the cut of a separation cascade, defined as the ratio of the product rate to the feed rate, it is always possible to separate a multicomponent mixture into two specified groups of components, a light group and a heavy group, in just one separation run. The cut is equal to the concentration sum in the feed of the components in the light group. The effects of the cascade length, shape, and feed location were studied. The results suggest that without using complicated cascades such as the M-cascade or the Q-cascade the separation of the middle component can be easily achieved.