I have one ADC, whose channel 1 to 4 will start conversion at x time and channel 5 to 8 will start conversion at y time. May I know how to use the same ADC in an STM32 microcontroller to sample at different frequencies for different channels??

i am working on ADC oversampling using STM32 nucleo board. I have increased 2 bits by using appropriate oversampling ratio and bit shifting. But when i used lower sampling time i observed less % error between expected v/s measured ADC count then high...