A system, method, and computer program product for performing edits on related curves by automatically defining an associative entity that is upstream of either curve being connected. The connecting entity is called an ‘intermediary’. When creating a connection between curves, irrespective of where they appear in the associative tree, their geometry is made dependent on a common intermediary that is placed upstream of both curves in the tree. With this structure, both curves are related to the intermediary but retain all the properties of being connected to each other. Any edit performed to either curve is redirected through the intermediary such that both curves are simultaneously modified, providing the user with bi-directional propagation of edits. The user does not need to keep track of the order that the curves were related.