How to remove xdata entries using biber --tool_resolve --tool (after resolution)

How to remove xdata entries using biber --tool_resolve --tool (after resolution)

Consider the file myrefs.bib containing the following biblatex entries:
@XDATA{pom,
  EVENTDATE  = {1999-12-31/2000-01-01},
  EVENTTITLE = {Party},
  VENUE      = {Somewhere},
}

@PROCEEDINGS{pomp,
  CROSSREF = {pom},
  DATE     = {2000},
  EDITOR   = {Me, Myself and I},
  TITLE    = {Party-report},
}
I would like to convert this using
biber --tool_resolve -g mybiber.conf --tool myrefs.bib
to get
@PROCEEDINGS{pomp,
  EVENTDATE  = {1999-12-31/2000-01-01},
  EVENTTITLE = {Party},
  DATE       = {2000},
  EDITOR     = {Me, Myself and I},
  TITLE      = {Party-report},
  VENUE      = {Somewhere},
}
Can this be done? What would the corresponding map in mybiber.conf look like? (I know that fields can be removed using map_null="1", but I haven't found such an option for entries.)