This is it, to be implemented ASAP:

1. ensure that custodian sales are found NOT subject to the requirement to be non-nominal; then add a constructed variable: NOMINAL_CUSTODIAN_SALE=1.

2. After finding a T2, search for any qualifying transactions on descendant properties of the T1 which occur before 1942-03-04, and output a constructed variable with a count of these: T1_T2_INTERVENING=5. 

3. After finding T1 and a subsequent custodian sale T2, search for NON-NOMINAL sales to JCs on any descendant property of the original property between the T1 date and the custodian sale date. In such a case, abandon construction of the original row and instead construct a new row in which that non-nominal sale is the T1 (retaining the already-found custodian sale as T2).

4. After finding T1 and a subsequent custodian sale T2, and assuming action #3 does not cause the row to be rejected, search for NOMINAL sales to JCs on any descendant property of the original property between the T1 date and the custodian sale date. Output a constructed variable with a count of these (NOMINAL_LATE_SALES_TO_JC=x).