A system for diverting fluid in a borehole string includes an object configured to be deployed in the borehole string. The borehole string includes a plurality of fluid ports defining a plurality of zones along a length of the borehole string, each fluid port extending from a fluid conduit in the borehole string to at least one of: an annular region of the borehole string and a subterranean region. The object is configured to be advanced by a fluid to a fluid port to obstruct the fluid port and divert the fluid in the borehole string to another fluid port. The object includes a core portion made from a first material having a first property, and an outer portion at least partially surrounding the core portion and made from a second material, the second material being deformable and having a second property that is different than the first property.