The simple answer is no. The NIC card in it is obviously something off the shelf and I'm sure there might be a way to brick it and use another instance on the card. I don't know if the firmware is able to deal with a second interface instance on the same NIC.
However, what's stopping you from making the connection from the switch or router? Just make a firewall rule or a route through the switch(es)
Can't really provide any targeted suggestions on how to proceed as we don't know the scenario you need two NIC's for, but one option would be to use an Ethernet - serial adaptor plugged into a serial port on the control system to get you the second NIC. May or may not do what you need depending on what you are trying to achieve...
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However, what's stopping you from making the connection from the switch or router? Just make a firewall rule or a route through the switch(es)