OAuth 2.0 using Thingworx Content Loader Services

This is related to consumption of external REST APIs from Thingworx. I am trying to use Content Loader Services for this. The problem is that external system uses OAuth 2.0 instead of basic authentication. So that means to consume any API we need to pass bearer token instead of Username password to get response each time. And to generate the Beaer token there is Auth API, but to consume that we need to pass username and password externally( login page comes up). I just wanted to understand if there is a way in Thingworx we can achieve this. Or any other examples you guys have tried accomplishing OAuth 2.0 mechanism.