https://en.wikipedia.org/wiki/List_of_long-period_comets https://en.wikipedia.org/wiki/List_of_long-period_comets https://en.wikipedia.org/wiki/List_of_near-pa

https://en.wikipedia.org/wiki/List_of_long-period_comets https://en.wikipedia.org/wiki/List_of_long-period_comets https://en.wikipedia.org/wiki/List_of_near-parabolic_comets https://en.wikipedia.org/wiki/List_of_near-parabolic_comets The grouping is hard to figure out, as gravity would likely pull them together. But if a comet approached nearer the sun, or swung by some high gravity planet, it might break up into a few smaller comets along the way. An example of a recent famous comet that broke up is Shoemaker Levy 9. https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9 https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9