[meteorite-list] mainmass

[Andreas Gren]

Dear List
Is there an official definition for mainmasses?
A)the mass that is left after classification .
ok no problem
B)over 50% of one meteorite.
 What's up with meteorites where several peaces were found ,then three
stones could be the mainmass  but there could be one stone that's bigger as
each of the three but less than 50% ,so the biggest would not necessary be
the mainmass
C)less than 50% of one meteorite.
So the problem in B)would be solved ,but when there is only one stone and I
have a mainmass with less than 50% it could happen this stone broke/ore be
cut
and suddenly another person have the mainmass because each of the fragments
are smaller than the slice person x has and person x did not know that
he/she is suddenly the owner of the mainmass .
any help ?