By default, DITA2Go forces an index level break for a See or See also index entry. For example:
To prevent arbitrary index level breaks for See and See also entries
[Index]
; LevelBreakForSee = Yes (default, always force a level break before
; See and See also entries), or No (break only for explicit colon)
LevelBreakForSee=No
When LevelBreakForSee=No, a level break occurs for a See or See also index entry only if an unescaped colon precedes the See or See also clause. See §16.5.4 Treating commas as potential index level separators.