Remove values from ENUMLIST previously added in a record

[Eduardo_Alvarez]

how to avoid to have duplicates, I have a ENUMLIST getting values from a reference table column:

SELECT(CONCEPTOS_REF[CONCEPTO], [TIPO] = [_THISROW].[TIPO])

is possible to remove from the list the values previously assigned to a record?

I have this formula where I get list of values already recorded for specific POSTE_ID:
SELECT(CONCEPTOS[CONCEPTO],[POSTE_ID]=[_THISROW].[POSTE_ID])

I only need to remove values returned by this list to the previous list and avoid user select values on this last list

rgds!