What does the following search tell you when you run it for the log source under question? The host value should give you the name of the HF.  index=<your_index> sourcetype="your_sourcetype"
| dedup host
| table host     If this doesn't give you the desired result, then try the following (Ignore the name of the indexers in the search and focus on the others. You'll find the name of the HF):  index=_internal "sourcetype_name"
| dedup host
| table host   ++If this helps, please consider accepting as an answer++ 
						
					
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