Hi Basu,
In the Material master filter setting you can add a filter for the material number range for which the replication should happen .
For example you want to replicate only the material from number 1000 to 5000 alone then create a filter for the Table 'MARA' , material number field 'MATNR' and operand (OP) as 'BT between low and High' and then set the low value as 1000 and high value as 5000 in the material master filter setting as shown in the above screen. Start the initial load ,this initial load will replicate only the material between the number range 1000 to 5000 only and all the old once will not be replicate. After the initial load run successfully don't forget to set the low and high values to the original value.
Regards,
Suresh