The way something was told will never be told the same way as someone else. Though the general idea is the same, the experience when being told something versus telling someone else about it is very different. So yes, there is a part of "we know" that remains personal to an individual.
it had three legs!
and four arms!
What one knows is not purely what they personally know. It can be affected by what others have told them and the environments they have been in. For example, the lady in white in this scene was told information by the other two from the slide on the left. Though she knows something in this situation, it is not something only she knows. She based her knowledge off of something someone else already knows.
It is can equally easy to communicate "I know" and "we know". The biggest reason as to why it would be more challenging between the two would be that when it is with a singular person because the person may be forgetful or miss out on something they should have said.
When a one person+ group explain something to someone it may be easier than if a person says it on their own. This would be the case if it is difficult for a person to tell someone something on their own. It could also add more details when a group tells someone because they could potentially be adding more details that the singular person would have missed if they were by themselves.
Communities of thinkers revolve around discussion and that what personal and shared knowledge allows for. We talk about what one personally knows and expand on it by reflecting more ideas, making it shared knowledge.