We consider the problem of offset selection for fixed-time signals in a network of arbitrary shape so as to increase the bandwidths that vehicles on multiple routes receive. Assuming that all signals have a common cycle, we utilize the concept of relative path offsets and formulate the problem of maximizing a weighted sum of path bandwidths. This leads to a nonlinear optimization problem. We demonstrate how this problem can be converted to a mixed-integer linear program; hence, providing a scalable computational framework. Our approach is in fact a generalization of a previous method in which the single arterial problem was found to be equivalent to a linear program, and is distinct from the traditional formulation as a mixed-integer program. We further show the practicality of our approach in a case study of a traffic network in San Diego, California.