Geodetic and astrometric VLBI has entered a new era with the implementation of the VLBI Global Observing System (VGOS, formerly known as VLBI2010). These broadband and dual linear polarization observations aim at an accuracy of station coordinates of 1 mm and a reference frame scale stability of 0.1 mm/year. Although the extended brightness distribution of many of the radio-loud AGN observed during VGOS sessions is resolved by the interferometer, the established processing chain still treats these objects as point sources. We investigate the impact of source structure on the visibility level and develop tools to remove the structure from the data as early as possible in the process. Here we present our approach and show results obtained from observational data.