Assuming 3 sensors on same bus means time sequential addressing. Find an I2C peripheral with 3 sets of SDA and SCL pins. Then you can select each sensor. CubeMX does not do such advanced dynamic hw reconfiguration.
By extension, if you are short of pins, use one shared SDA and 3 different SCL. The inactive 2 SCL are SW switched to SCL output low to make the sensors time freeze regardless SDA activity. Some SW tweaking and oscilloscope checking anf pull up rssistor tuning maybe required. Overall n + 1 pin for n sensors and not shutdown to manage.
