Can you give me some more information? If you’ve got an ethernet interface and you’ve removed the jack, let me know what the jack part number is. If you’re building a circuit from scratch, what’s the part number of the physical interface (PHY) or switch you’re using.
We can look in the datasheets to find hidden load resistors and magnetics.
The simple answer is, I bet you could get away with a 4-pin 0.1in header and a couple 100 ohm resistors, one placed across each pair at the connection to the PHY. You could re-use a scavenged cable, like a CDROM audio cable. Carefully remove and de-crimp the ends, and solder your pairs in an order of your choosing, then re-assemble. Then the wires would stay together.
Let me know some more info and I can get a better answer for you.
Thanks,