Task group in Transaction type vs Sales Item type

Hi Experts,

We have two options to implement task groups either at Header level(Transaction type) or at Line item level(sales item type). We have requirements to have one transaction type and multiple sales item type related to the pos transaction type.

If we create different task groups with different tasks as per the behavior of each sales item type and apply those task groups at sales item type level, would that be feasible? Which task group takes precedence, one at the header level or at the sales item type level, if we keep only one task group at header and different task groups at line item level ?