I could link the Radius server with SN0116CO for 3rd party authentication.

Is there any way to use the group in Radius server to set the group permission for the account access right? 

You could set the value in "Vendor Specific" in Radius server setting.

Please set the group name in the attribute value.

For example, if there is 3 groups in Radius server, which are named as g1, g2, and g3.

Then insert g1, g2, g3 in the value, please refer to the attachment.

After that, please create groups with the same name and set the access right of the group in SN unit.

For example, the account "snuser" is in group "g1", which only has the permission "user Admin".

When the user account is used to login to SN unit, it will follow the access right of the group "g1".

If the user account is added into 3 groups, it will have the access right of the 3 groups.