exporting selected account subtree

[TMaynard]

Hello list,
    I new to the enjoyment of gnucash and have a question about exporting
  transactions specific accounts (from a portion of one chart of accounts)
into another chart of accounts.   The export command seems intended to
export an entire file or COA  ...not for exporting a partial selection of
accounts from a COA.

    In cases where gnucash is used separately for a business and for
personal accounts it is simple to setup a placeholder account and
subaccounts that capture business related  expenses which occur/flow
through the accounts of the personal COA. In this case , the personal COA
can contain a subtree of accounts identical to the business COA categories
(at least for those  categories that actually occur). It would be
preferrable to export only that placeholder subtree of account transactions
to be then imported into the business COA. I do not find a tool for
exporting just a subtree of accounts  into a file that can be imported into
another COA. Is there an undocumented method?

Gnu cash has been good, and this would be another plus
Rusty