Combine Rows Into Single Cells By Condition

I'm importing some data from an HTML table into excel, it all formats pretty well except that some of the data appears on multiple rows.

A B C
1 01.02.06 John
2 Bob
3 Sam
4 02.03.06 Jim


What I need:

a b c
1 01.02.06 John, Bob, Sam 3
2 02.03.06 Jim 1

What I need to do is get all the items in the colum B which are listed under the same item in column a, in the first case John Bob and Sam and put them all into the same cell. I then want to delete the empty rows. It's important that this is done by testing to see if column A is blank, rather than using the date.

then in column C I want to count the items in column B,
ideally then repeat the script for the whole sheet.

Not a clue of the type of syntax I should be using though!
In fact there's probably a better way of importing the data from the HTML so it doesn't even need to be done this way! of course I'm oblivious to it. Auto Merged Post Until 24 Hrs Passes;Thinking maybe I didn't make myself properly clear....

If a cell in column a is empty then it means the item in column b needs adding to the end of the item in the row above in column b.

I then want to count the items in column b.