Find excisting values, make them grouped under the new value
 

I have 2 worksheets Sheet1 and Sheet2,
In sheet 1, I have a large register, in Sheet 2 I have new lines/
versjons for the Register in Sheet 1.

1. How do I automatically cut from Sheet 2 and paste it to the last
row in Sheet 1?
2. How can i search and find rows, where the ID = the ID in Sheet 2?
3. When There is a new row (with a ecisting ID) the excisting sould be
superseeded by the new one in Sheet 2, and then "grouped" under the
new versjon so that only the last versjon show at level 1 when using
the Group function??