To open interpolated ancestor elements before starting the current block:
[DocBookOpenBefore]
; para format = elements to be opened, with any other elements
; nested under them, before the current block element starts.
somefmt=someancestor
Use this setting to force opening of elements when [DocBookParents] does not suffice.
For individual cases, you can insert a DocBookOpenBefore PI marker in the paragraph for the current block element instead, with content the name(s) of the element(s) to open. You can also use a DocBookOpenBefore PI marker to override a [DocBookOpenBefore] setting when you want to open a higher (or lower) ancestor than the setting specifies.