Data filters are synchronized between the CM4D and Results databases using an index map. In the CM4D databases, an index value is assigned to a filter which is then used to apply the filter to data in the Results database.
An index value can be any number from 1-42.
The filter letter in CM4D database is inconsequential to the Results database. Therefore, filters with different letter assignments in two databases can combine in the Results database by assigning the same index value.
Within a CM4D database, the results index value must be unique. The Routine, Feature and Sample filters are considered separate sets of indices.
The Results Index is set in the DataUtility Filter Manager. See here for more information.