Business Partner replication from ECC to CRM based on Company code

Hi:

I got this requirement where we need to transfer customers from ECC --> CRM. Customers specific to a company code.

Trying to maintain Filters for  CUSTOMER_main--> KNB1- BUKRS to filter customers by a certain company code.  I get this error " Table not maintained in smoftables."

Checked table " SMOFFILFLD" to see there are no entries for KNB1.

While I could check with my superiors on restricting transfer of customers based on Sales area data, as KNVV and KNVP data is maintained.

I would like to know if I can proceed with adding new table KNB1 to this table. If this is not recommended kindly suggest one.