Returns or sets the text between alphabetic groups (entries that start with the same letter) in the index. Corresponds to the \h switch for an INDEX field. Can be one of the following WdHeadingSeparator constants: wdHeadingSeparatorBlankLine, wdHeadingSeparatorLetter, wdHeadingSeparatorLetterFull, wdHeadingSeparatorLetterLow, or wdHeadingSeparatorNone. Read/write Long.