Can we plan item at category level ?

Summary:

Our customer produces different item every month, once the item released they will discontinue soon (max 6 month - 1 year product end of life for each item). The module for supply and demand planning provide the plan recommendation at item level for future executions (plan order, sales order or PR).

Is there a way for us to plan at category level since there will be no same item to plan and the forecast for the item won't look good (only 6 months).