Hi Varun,
In this case you just need to maintain Numbering schema.
Path: cross application components->sap products->product category-> Define No schema
Click on New entries 1 5
2 5
3 8
and save.( it product occupy 18 digits).
Then you need to do output format & storage format for product.
Path: spro->cross applicouation components->sap products->basic settings->Define output Format and storage format of product IDs.
Hear you need to give 18 length and mark all check boxes and save it.
once these settings done make filtering setting in R3AC1.
Replicate your requried materials from ecc to crm.
Run Object: Material in R3AS.
Thanks,
Hari