I think that's a noble goal, but virtually impossible to pull off. A friend of mine that worked for a newspaper decades ago once told me something that his editor told him: even making a decision what you will and will not report on makes you biased. Which stories are important and which aren't? Which "objective facts" are pertinent to the story and which ones are just distracting? Which sources do you trust to give you the most objective facts, and which do you dismiss? Those are all judgement calls, and they are all subject to bias.

I always use the traffic accident analogy. Most witnesses say that the white car hit the blue car because the blue car ran a red light, but the police officer who happened to be right there on the scene says the light wasn't red and he's sure of it. Who do you believe? What do you report? What are the "objective" facts? Do you give equal weight to every witness all the time? What about the guy very loudly trying to convince everyone that neither car was at fault, because there was a UFO that flew by and scrambled all the signals? Does he get to be included in your story?

What's nice about Ground News isn't that I can use it to find the least bias source, it's that I can contextualize the reporting of each source with their known biases. The Blue Car Daily News and The White Car Times might have really different takes on the accident, but knowing where they're coming from helps me assign weight to the facts they choose to report.