How to auto generate Data from one Workbook to another? Unique Identifier?

Hi,
Time
I was wondering if anyone would know how I could go about doing this? I have two different spreadsheets which are automatically generated from external systems I receive each week, I need to move values from one to the other. I am moving hours worked from one sheet to another the problem being that one person can have multiple entries because each time entry is claimed against a work item.

For example my data could look like this

Name Hours Item Date
Joe 1 5 AAA Oct 1st
Joe 1 10 AAA Oct 8th
Joe 1 2.5 AAA Oct 1st
Joe 1 20 BBB Oct 1st

What I am trying to do is take that data and place it into a second sheet where the hours would be accumulated for each Person, Date, Work Item

So based on the data above I would want a script I could run that would take the data from above and insert it into my second workbook where every entry for each user would accumulate the hours entered for each date and work item.

So it would take the data above and accumulate the entries that have the same date and Item into one entry on the new workbook, (The second workbook is used on an ongoing basis so it already has pre-existing entries.) So ideally I would like the formula to adjust the fields in this workbook if they match the time entries from workbook 1. So it would take all of the data from Workbook 1 and accumulate all the values for each name that has a corresponding Item and Date.

So it would accumulate the data above to take both line 1 and line 3 add them together and insert that new value into the second workbook where the name item and date matches.

Hopefully you can make sense of what I am asking.

If anyone can recommend a way of doing this that would be great I am semi familiar with excel but I have not done a lot with automating spreadsheets or linking workbooks together.

Again any information you could provide me would be greatly appreciated as it would reduce a lot of manual time entry, where I have to go one by one and enter this data manually row by row for about 100 employees.

Thanks.

Thanks for the response.

I am not sure if that would work as I need it to sort by date as well, so for each week it would have to take the data from the first workbook and divide it into the corresponding weeks (by date). and enter it. I have more rows and columns on my sheets than I used in my example as the remainder of the workbooks are just calculated fields based on these entries.

Thanks.