Create a filter in a variable option

Something like this:
PS : if an entry has a remaining amount, it is Open. So I put a filter (and currentindex) on Open. This should give better reading performance.

recCustLedgerEntry.RESET;
recCustLedgerEntry.SETCURRENTKEY(Open);
recCustLedgerEntry.SETRANGE(Open,TRUE);
recCustLedgerEntry.SETFILTER("Document Type",'%1|%2'
  recCustLedgerEntry."Document Type"::Invoice,
  recCustLedgerEntry."Document Type"::Bill);
IF recCustLedgerEntry.FINDSET THEN
  REPEAT
     CLEAR(recNewTable);
     recNewTable.TRANSFERFIELDSrecCustLedgerEntry);
     or
     recNewTable."Field 1" := recCustLedgerEntry."Field 1";
     recNewTable."Field 2" := recCustLedgerEntry."Field 2";
     ...

     recNewTable.INSERT(FALSE);
  UNTIL recCustLedgerEntry.NEXT = 0;

You can create a codeunit and put it in the OnRun-trigger.
Or a report and put it in the OnPreReport or OnPostreport trigger.
Or in a form in the OnOpen-trigger. Or in a function that is called by a button on the form.
There are so many possibilities.