We have continuted study of the relative Drinfel'd commutant of a full subcategory of a fusion category. We have introduced a relative torus algebra as a subalgebra of a relative tube algebra and considered an action of the S-matrix on it, and proved the relative Verlinde formula. When the subcategory coincides with the entire category, this is the usual Verlinde formula for the Drinfel'd center, and if the subcategory is trivial, this gives the original fusion rules back. So in the general case, we have an "interpolation" between these two opposite extreme cases.