Dynamic Expanding/Contrasting Groups of Rows?

I have a spreadsheet I am trying to improve which compiles a list of materials from multiple "groups", which the items for each group are in another sheet/tab. The "Total" sheet compiles all of the items in the various group sheets. I would like the groups of rows on the Total page to be dynamic, expanding or contrasting rows as needed when more or less items are added to the group sheets.

I have tried a few different strategies from Googling, but to no avail. If anybody can make that work it would be appreciated!