Hi @Quantum ..
You can use this command:
| rest /services/server/info | table host host_fqdn server_roles
Please check this Splunk document:
one way to get some hints for its role is use REST API. For local server you can try
| rest /services/server/roles splunk_server=local | fields splunk_server role_list
Of course this expecting that those servers are added as a search peers to that node. You can add only one splunk_server only on command arguments, but you could use wildcards.
Another way is use curl on command line to access remote to those servers.