Global Change or filter based on Min and Max dates

Question

Hi Guys,
Hopefully there is a genius out there that is an expert with filters and or global changes, I am after a solution and can’t work out if it is possible to do in P6.
Based on a filter (using codes to select a group of activities) I want to write a value into two date UDF Fields can I:
Run a global change to give the earliest and latest date in the group and write the result to all tasks in the group? or
Is there a mindate maxdate option in Global change or filter? Or
If these tasks were grouped in the activity view can a global change be written to fill down the dates that the summary level is displaying, which are essentially the min and max dates of the groups.  
I could do this pretty easily in excel but I have over a 100 projects and doing the import one at a time is not feasible.
I could create LOE’s but as my variables are constantly changing and due to the volume also not an option.
Summary bars are not an option eithers as I am writing the UDF’s to get all the bars I want on one line, 
An option for me might be to do it using Legare but I would prefer to see if I can get it done in P6 first.
Cheers
Rob

Answer 1

Yes, you can do it in one report.
I created a sample report from efashion:
Year | Lines | Sales Revenue
2001 | Accessories | $250
2003 | Accessories | $550
2001 | City Skirts | $1050
2003 | City Skirts | $1150...........
Create 2 variables 1) Count and 2) Difference:
1) Count  as formula - =Count([Lines]) In Report
2) Difference as formula - =Sum([Sales revenue]) Where (Max([Year]) In Report = [Year]) - Sum([Sales revenue]) Where (Min([Year]) In Report = [Year])
You can replace the formula with your report variables. Then just drag Site ID, Count and Difference variables to your report.
Thanks
Jai