[TYPO3-english] TypoScript: how to only wrap something if some other COA property is not empty

[Stephen Bungert]

I have the following TS.

It does almost everything I need, but I only want 
temp.mainTemplate.subparts.NLCONTENT.1.20.stdWrap.ifEmpty.wrap

if temp.mainTemplate.subparts.NLCONTENT.1.10 is NOT empty.

Currently the ifEmpty wrap is always applied if

temp.mainTemplate.subparts.NLCONTENT.1.20.10 is empty, even if

temp.mainTemplate.subparts.NLCONTENT.1.10 is empty.

which then gives temp.mainTemplate.subparts.NLCONTENT.1.stdWrap something to 
wrap

Here is my TS (can anyone help me solve this?)

temp.mainTemplate {
  subparts.NLCONTENT = COA
  subparts.NLCONTENT {
    1 = COA
    1 {
         # Get article1  content
      10 < styles.content.getArticle1
      10.stdWrap.required = 1

        # Get sidebar 1 content
      20 = COA
      20 {
        10 < styles.content.getSidebar1

        10.stdWrap.wrap = {$cornerTableSidebar}|
        10.stdWrap.required = 1

        stdWrap.ifEmpty.wrap = {$cornerTableSidebarEmpty}|
      }

      stdWrap.wrap = {$cornerTableStart}|{$cornerTableEnd}
      stdWrap.required = 1
    }
  }
}