# How I can use FindFit to simultaneously fit two data sets to two equations having shared parameters? [duplicate]

I think that FindFit package with the method Nminimize yields global minimum if initial values of adjustable parameters are chosen properly with some constraints. I did use it to fit one data set to one formula but I wonder if one can hint to me how I can make a simultaneous fit to two different data sets and two different equations with some shared parameters.