Question on Setting/Building Navmesh / Navmesh Agent Path

Hello everyone, I'm trying to understand how to (and if) I can set my own paths for Navmesh Agents to follow. I've looked at the Navmesh and NavmeshAgent classes but am a bit confused on when to use one or the other // and what can and cannot be done to set paths (conflicting forum posts).

My Situation:

I'm having an issue where agents with paths become blocked by other agents. Of course, the agents will try to go around each other, but if they got blocked on both sides, they will just sit there and be stuck until one of the agents moves out of the way.

What I would like to accomplish:

When this occurs (after I have determined that an agent is "blocked"), I would like to set the current end node way-point to the closest way-point available, then calculate a new path from that way-point (essentially wanting to custom set the first new node point, then allow the system to calculate the rest of the point to the destination).

The image below shows something like what I am trying to achieve. The agent is blocked, so rather than its current 0,1,2 path -> I would like to set to something like 0,3(being the best available node where no "blockage" is detected), then allow Unity to compute the remaining path to the destination. Or, said another way, to reject point 1 and force a different node to be the next destination.

Any ideas are appreciated.