Mon - Not sure exactly what you are trying to do....but if you are trying to get some part of the source file name(s) to become a field in your data set, you can add/edit or separate the source file name by defining separator and adding some text to the file name. i.e. a set of incoming MonthlyFile.csv files could renamed to:
January_MonthlyFile1.csv
February_MonthlyFile2.csv

When you import and batch append these two files using Omniscope, the Source field for all records can be expanded using the Expand columns operation and specifying the separator "_" and the combined data set will then have the text from each file name as a separate column/field with the same value for all records that come from the same file:

[Source1] | [Source2] | [Field 1....etc.]
January | MonthlyFile1.csv |
January | MonthlyFile1.csv |
February | MonthlyFile2.csv |
February | MonthlyFile2.csv |

You can rename the [Source] field to ["Month"] and then use this field in the appended data set for named queries, filtering etc.

You can add as many arbitrary values as you like to the file name(s) and expand the Source field into any number of new fields/columns to be added to the data set.