Is there a way to manipulate the fields being sent to Moneris through the JotForm administration portal?

For example, 

The platform Conexsys, they use an embedded form in their application to process payments and connect to Moneris using their API. This allows them to determine which fields they want to pass to Moneris when the transaction is submitted.

See screenshot to see how this can be done. 

Let me know if this is possible, we would like to be able to distinguish which payment was processed from which form.

It would not be possible to specify fields to send to Moneris out of the Moneris payment element fields. 

An alternative for this could be asking for the same information in other text entry fields, like the First Name and Last Name.

You can use the shortcut CTRL + F (PC) or Command + F (for Mac) to search for the same First/Last names and identify specific submissions from the Moneris payment logs based on the form submissions.

Let us know if you need further assistance, we'll be happy to help