Hey ,
You are getting confused again, please see the next quick graphic for better understanding:
Sorry for not being so detailed, I did it really quick. What I am trying to show you there is a simple construction of a cluster that share the same portgroups not only for VMKernel but also to connect virtual machine as in essence is just a Distributed Portgroup not a "vm adapter or vmkernel adapter". On both of them you can connect a VM or a VMKernel as you need to.
A VMkernel or a vNIC (VM Adapter) is always connected to ONE portgroup, the difference between them is that the VMKernel is used for VMware traffic such as vMotion, MGMT, vSAN, etc and the vNIC is used to the Virtual Machines that you are deploying on top of your hosts.
So going back to the problem you have there is no possibility that your current hosts are all using the same VMKernel as there is one per host and they cannot have the same IP as you would have conflict and disconnections everywhere. But yes, they share the Distributed Portgroup that have the VLAN281 for MGMT (as I can see in the picture). Why is that? Becuase as the name says this is a group of ports which means multiple VMKernels or VMs can be connected to the same one without any issues.
To finalize, what you need to do for any new host is to create a new VMkernel on the portgroup that you are using for MGMT on the other hosts with a unique IP per host.
Hope I was clear with the explanation however if you still have doubts I can go more in deep.