Multiple Sheets Match & Index filtering by sheets

Hi there. So I'm brand new to this forum and am grateful for the assitance.

I'm attaching a dummy spreadsheet that I need help summarizing. Basically there are (and will be more) sheets of data dated by week. As the Table is constantly changing based on the user's sorting I think I need some sort of Index and Match combination.
My goal is to:
1. sum columns of the agents based upon choosing one, several or all sheets
2. Populate Agents based on an individual 'Office' or all offices.

Thank you VERY much!
Julian