Samsung Z Fold 5 + Z Fold 4 Call Samsung Z Flip 5s, Z Flip 4 & Moto Razr Incoming & Outgoing Calls

Samsung Z Fold 5 and Z Fold 4 trying to call Samsung Z Flip 5, Z Flip 4 and Moto Razr 40 Ultra on Viber, WhatsApp, cellular, Signal and Viber in a split screen mode. Unfortunately, I got the error "You can&place a WhatsApp call if you&already on a phone call". The same problem is with the Signal. However, it is possible to place calls on Viber & Telegram on the same device at the same time.