Feature Request: distinguish a tx order comes from the mempool or rpc_server

Problem Statement
We need an easy way to distinguish whether a transaction order comes from the mempool or the RPC server. Our build algorithm relies on this distinction, but currently, there's no straightforward method to determine the source.
Current Situation

Transaction orders can come from two sources: mempool and RPC server
The build algorithm requires knowing the source of the transaction order
There's no clear mechanism to identify the source of each transaction order

Desired Outcome
A reliable and efficient method to determine whether a given transaction order originated from the mempool or the RPC server.
Potential Impact
Implementing this distinction will:

Improve the accuracy of our build algorithm
Enhance our ability to process transactions appropriately based on their source
Potentially optimize performance by tailoring our handling based on the transaction source

Possible Approaches (To Be Discussed)

Add a flag or metadata to transaction orders indicating their source
Implement a tracking system within the software to log the origin of each transaction order
Analyze characteristics of the transaction orders that might inherently differ between mempool and RPC server sources