How can we maintain Hierarchy at Quote line item level via customized method

Siebel IP22.12

Hello All,

Hope you are doing well !

I have a XML message including Quote header and line item information. Instead of using Quote/Quote Line Item BC to insert, I want to Insert this XML in custom BCs.

Is it possible to maintain Product level hierarchy while inserting the line items, without using RCOIS ?

I want line items with Root Product line item as parent and rest following hierarchy 

Thanks in Advance