Yes, you can. The vendor is set to 'unknown' because this value is an SNMP value. If Orion can't authenticate than Orion doesn't know what the vendor is. So if you want to override this, you can do so by creating a custom property for the nodes like 'GroupName' and then next to each node, give the node a description like 'NodeDescription'. Then when you go back to the Orion web UI, edit the All Nodes resource and group by your new custom property name of 'GroupName'.
Note that if you don't populate a field for a node though, that node will again fall under 'unknown'.
Also, cntrl+C and cntrl+v are supported for copying and pasting across multiple cells in the Orion Custom Property Editor.
Could you please give me more details about how to create above solution