Black hole formation as seen by a distant observer
Given that matter can never cross the event horizon of a black hole (from an external observer point of view), if a black hole is "fed" with a large amount of matter then the new matter will eventually become extremely compressed, and presumably would be compressed below its Schwarzchild radius.
Would secondary black holes eventually form near the original black hole?
As an alternative one could also imagine that the combined mass of the original black hole and the new mass around the event horizon becomes contained within the Schwarzchild radius of both masses, and so a new event horizon forms, "swallowing" the new mass around the edge of the original black hole.
This mechanism would allow black holes to swallow mass in a finite time.
Would this contradict GR predictions?