OISD - Create service Products

Hi Experts,

In OISD, iam not able to assign Task list for Same Plant & Service product with different work centre.

Plant & Service product are key fields & we cant have multiple entries for the same. But the Customer has a requirement to assign different Work centre & task list per Plant & Service Product combination.

Could you Pls let me know how we acheive the above functionality.

Regards,

Karthik