Group Activities in Gantt Chart

[BKGLTS]

Hello,

I have a dynamic gantt chart setup in excel so that as activities are added to a cell range they automatically pop up on the gantt chart.
Columns of source data are:
A=Item
B=Description
G=Start Date
H=Duration
I=End Date

There can be a lot of activities and they all show up individually on the gantt chart.
However, I want to group them so that categories show up on the gantt chart instead of each individual activity.
But want it to still take into account the individual start and end dates of each activity when determining the duration of the category.
AND If possible I really need any new data columns to make this work be in Column J, K or L.
(I have dynamically linked cells in this data range and trying to insert a new column anywhere before Column E makes it lock up.
My source data for the gantt chart looks like this:
=Schedule!$B$2,Schedule!$G$2:$H$2

Horizontal Axis is from Description column.

Thank you!
B

 

[BKGLTS]

I found this but it is not what I need.

Group Project Activities to Make Readable Gantt Charts - Excel Gantt Charts

In Excel Gantt Charts part of our project management series, we have discussed about how using Conditional Formatting and Formulas we can make a gantt chart like this: But when you have large project plans, gantt charts like above can get pretty intense and hard to read. So a better approach is...

chandoo.org

It creates new rows and you have to manually edit the formulas every time for the MAX.
I just want to be able to have a column J that I can quickly type a group name in for each activity and it will leave the original source data alone and somehow report it correctly in the gantt chart.
Only thing I can think of is summarizing my original source data into another table that is somehow filtered by group column and sums and takes the min start date and the max end date of all the activities to create a new data set for the gantt chart to pull from.