Since you can add a search restriction on a role base (i don't use it) it is whiser to add for every needed department (or groups of departments) it's own index. You'll generate a few more indexes, but on the indexer it won't eat much power.
Since a summary index is like a normal index, but w/o an own secstofrozen value.
And it don't count to your license.
A tutorial is here:
http://docs.splunk.com/Documentation/Splunk/7.0.1/Knowledge/Configuresummaryindexes
But in short, you have a search which will select your needed data and will write it to a summary 😉
E.g. a collection of license data for longtime evaluation.
index=_internal source=*license* type="Usage"
| fields st, idx, h, b, i, _time
| bucket _time span=1m
| stats sum(b) as bytes by h st idx i _time
| lookup sysmgmt_hosts guid as i OUTPUT name as srv
| eval output=split(h,".")
| eval anz=mvcount(output)
| eval h=if(anz > 1,mvindex(output,0),h)
| eval output=split(srv,".")
| eval anz=mvcount(output)
| eval srv=if(anz > 1,mvindex(output,0),srv)
| eval indexer=if(isnull(srv),i,srv)
| eval type="license"
| fields - output, anz, srv, i
| collect index=sysmgmt_summary
... View more