Dear Sridhar,

Hope you are doing well.

Please switch-off  the VM and then click on the Network settings in the Virtual box and do changes as shown below:

In Adapter 1 keep it as NAT and in Adapter 2 keep it Host only Adapter

Make sure that in the Adapter 2 , Promiscuous Mode is Allow All

Make this above network settings for the all the VMs which you have created.

I think this will resolve your query.

Please Let me know if you have any further issue regarding this.

Feel free to contact us in case you have any query.