Hello, yes, it possible (secondary name server in ISPmanager)
You should connect the second server in the domain names menu -
external name server on first (master) server. The connection must be with administrator rights. Domain zones are created in the first server will be created on the second server as a slave DNS in the named (bind) configuration file. This records is not visible in the ISPmanager interface on slave server.
Also, you may need to configure option
ispmgr.conf such as DomainSlaveZonesPath for correct path to files with dns zones.