FA tax book accounting

Hello,

We have two fa books : primary (corp book) and secondary book (tax book linked with primary book).

Both FA books are assigned to same GL Ledger and accounting is allowed for both.

for FA primary book there is no issue, it's a classic normal accounting.

for FA secondary book we hope that the system account only the differences (the gap between books), how to do ?

Example 1 : asset cost is 4000 in both books

target accounting for FA primary book :

(D) asset account 4000

(C) Clearing account 4000

and no accounting for FA secondary book

Example 2 : asset cost is 4000 in FA primary book and 6000 in FA secondary book