Partner Determination using Product Category in Lead/ Opportunity

Hi,

I am working on CRM 5.0. I am working on partner determination for Lead/ Opportunity transactions. While determining partners the partners are getting determined properly except for a Product Category. I have defined a Territory and at "Line" level of my territory defined Product Category as the attribute of this category and assigned a Product Manager at this level. Now I want this Product Manager to be determined automatically in my transaction for a Product (in the transaction) belonging to this category.

Currently for other partners the determination is happening as per the Sales Prospect's data automatically. Pl suggest how to achieve determination pf Product Manager based on Product data. Shall I go for Partner Determination at item level?

Pl suggest any alternative, if any too.

Thanks and Regards

Ambar Adhav