Adjusting legend

Hi,

With a display name of ${__field.name} ${__field.labels.ifDescr}
I managed to get my legend looking like this:

Which is okay i guess, but i would much rather have the ifHCInOctets and ifHCOutOctets be replaced by ‘RX’ and ‘TX’. I looked in to the standard override options that Grafana provides, but overriding the ‘ifHCInOctets’ and ‘ifHCOutOctets’ also overrides my interface name.

What is the correct way to accomplish this? Maybe i need a more sophisticated regex?