how do I connect to internet via a USB modem while still accessing the work network via ethernet at the same time?

Hi guys,

I am connected to the work network via ethernet but the shared internet is extremely low and I would like to connect my USB 4G Modem. I can connect and get it up and running but the ethernet overrides my accessing the internet via the modem. So far the only solution I have found is unpluggint eh ethernet network cable but then i cannot work with files on the server. Is there a possibiliity of running both concurrenty?

Thanks for your help.