SQL data Import

HI,

I've 3 tables and have relations to each other. The Tables are A,B and C. 

I already have data on Table A. The last ID of the Table is 221 and I have another lists of data on the excel sheet. I want to import these data on the Table A where we already have data and the ID should starts from 222.

And also I have other B and C tables data too which satisfy the ID relations to the table A.

Anybody know about importing the data from excel sheet to SQL if already exist the data on sql table ??

Any help is highly appreciated.

Thanks