How to default "Transaction Subtype" field based on the Item in Report Orderless Completion page?

Summary:

We have a client requirement to default "Transaction Subtype" field based on the item in "Report Orderless Completion" page.

Once user selects the item in report orderless completion page, we need to derive the item category and then get the transaction type from a lookup by passing the item category. Basically, the main requirement is to default the transaction subtype based on item category lookup values.

Could you please let me know if this requirement is possible to do with page composer? (OR) Is there any web service (REST API / SOAP) to update the transaction subtype?

Navigator - Supply Chain Execution - Work Execution - Tasks - Report Orderless Completion