Improving and homogenizing time and space references on Earth and in space with an accuracy of 1 mm and long-term stability of 0.1 mm/yr is relevant for many scientific and societal endeavors, such as quantifying sea-level change. Reaching this goal is only possible by referencing the various geodetic sensors to one another on a unique well-calibrated platform. For instance, GNSS satellites require the Earth rotation angle from VLBI as an input parameter. Alternatively, an onboard VLBI transmitter (VT) on the satellites creates a space-tie between the VLBI and GNSS methods and can allow transferring the UT1-UTC information by jointly observing quasars and the VT. Previous work showed the feasibility of such a system where the UT1-UTC precisions from VLBI are assumed to be 20 and 40 microseconds for long and short baselines, respectively. In this study, Monte-Carlo simulations are carried out to obtain more realistic UT1-UTC precisions from VLBI Intensive sessions at four baselines, which are then transferred to the GNSS satellites. The quality of the transfer is assessed.