Alright; my attempt to explain the problem!

Iv got a 16 bit number, each bit represents weather a number, between 1 to 16 was in a collection.

0010 0100 0011 0001

Would signify object 0, object 4, object 5, object 13 and object 10 were in the collection;

But sometimes there may be more than 5 objects in the collection:

1101 1010 1011 0100

In this case; I must keep the objects with the highest numbers so it becomes

1101 1000 0000 0000

or 

1100 1000 1100 0010
to
1100 1000 1100 0000 - dismissing object 1

Any ideas?