The short answer is yes. Yes you can definitely wash the cloth diapers of different babies or siblings together in the same load. Have a newborn baby and a toddler in cloth? Wash together. Have a dayhome and multiple kids in cloth? No problem. If you have twins or higher multiples, same thing. All of the diapers can be washed together.
While you're at it, different styles of diapers can be washed together too. Pockets, flats, AIOs, AI2s, fitteds, covers or any other types of diapers can be laundered together as well.
When you should NOT wash different children's diapers together
Since your diapers are going to come out of the wash clean and ready to use again, there is no problem washing siblings' diapers together. The exception to this would be if one child has a yeast infection diaper rash. If your baby has a doctor confirmed yeast rash, you need medicated cream and the diapers need to be sanitized with bleach to prevent reinfection. Rather than bleaching diapers in every load while you treat the rash - which causes excessive wear and tear - it's usually better to switch the affected baby to disposables while treating the rash and resume cloth after it's cleared.
Another thing to be mindful of
One other thing to keep in mind when washing lots of diapers together is to not overfill your machine. Overfilling will result in a diapers that don't get properly cleaned and that will cause smells, rashes or buildup in the long term. About 2/3 of the drum full is good to aim for (check your machine manual to determine what is considered a 'full' load for your particular if you aren't sure).