Lines 2558~ of Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_adc.c does this.
However, it's not certain if ADC3 belongs to the same group as ADC1 or ADC2. If not, the use of ADC_ANY_OTHER_ENABLED is too restrictive, as we are working here only for internal paths which is available only for ADC3.
Thoughts?
2558 /* Software is allowed to change common parameters only when all ADCs */
2559 /* of the common group are disabled. */
2560 if ((ADC_IS_ENABLE(hadc) == RESET) &&
2561 (ADC_ANY_OTHER_ENABLED(hadc) == RESET) )
2562 {
2563 /* Enable Temperature sensor measurement path (channel 18) */
2564 /* Note: Temp. sensor internal channels available on ADC3 */
2565 if ((sConfig->Channel == ADC_CHANNEL_TEMPSENSOR) && ((hadc->Instance == ADC3)))
2566 {
2567 SET_BIT(tmpADC_Common->CCR, ADC_CCR_TSEN);
2568
2569 /* Wait loop initialization and execution */
2570 /* Note: Variable divided by 2 to compensate partially */
2571 /* CPU processing cycles. */
2572 wait_loop_index = (ADC_TEMPSENSOR_DELAY_US * (SystemCoreClock / (1000000 * 2)));
2573 while(wait_loop_index != 0)
2574 {
2575 wait_loop_index--;
2576 }
2577 }
2578 /* If Channel 18 is selected, enable VBAT measurement path. */
2579 /* Note: VBAT internal internal channels available on ADC1 and ADC3 */
2580 else if ((sConfig->Channel == ADC_CHANNEL_VBAT_DIV4) && ((hadc->Instance == ADC3)))
2581 {
2582 SET_BIT(tmpADC_Common->CCR, ADC_CCR_VBATEN);
2583 }
2584 /* If Channel 19 is selected, enable VREFINT measurement path */
2585 /* Note: VBAT internal internal channels available on ADC1 only */
2586 else if ((sConfig->Channel == ADC_CHANNEL_VREFINT) && (hadc->Instance == ADC3))
2587 {
2588 SET_BIT(tmpADC_Common->CCR, ADC_CCR_VREFEN);
2589 }
2590 }
2591 /* If the requested internal measurement path has already been */
2592 /* enabled and other ADC of the common group are enabled, internal */
2593 /* measurement paths cannot be enabled. */
2594 else
2595 {
2596 /* Update ADC state machine to error */
2597 SET_BIT(hadc->State, HAL_ADC_STATE_ERROR_CONFIG);
2598
2599 tmp_hal_status = HAL_ERROR;
2600 }
