Backup and reinstall 2nd instance of whatsapp on dual sim handset

hi!
i am a medical practitioner and use whatsapp as a convenient way of interacting with patients who for instance send me images of skin conditions to make a preliminary diagnosis whether the situation can be treated at home or whether a visit to casualty or my rooms would be wiser.
the problem is that i have a dual sim handset on which i have two instances of whatsapp. one for my private number which i can back up to my gmail and another for my emergency number which has no option for backing up to gmail although but does so locally. this last whatsapp only interacts with my second, emergency, number. this second instance of whatsapp though can backup to my phone. i would like to split my numbers to two phones with their individual instances of whatsapp but can only do a full backup to the cloud with the one instance, the whatsapp on my emergency number which is on local backup also needs to be reinstalled without losing chats - is this possible?
kind regards
gabriel