The answer is Yes. You should be able to do this with Power Automate.
You will need to build and refine your Flow. Your best bet would be to start with Copilot to refine what you are looking for. Below is a Copilot reply based on the information you provided to get you started,
Start by using “List rows present in a table” on your Source_table. Then add a Select action and map only the first column (the one that contains your group names). After that, add a Compose action with:
union(body('Select'), body('Select'))
That removes duplicates and gives you a clean list of unique group names. If a new group appears later, the flow will pick it up automatically.
Next, add an Apply to each loop over the output of that union step. Inside the loop, use Filter array to filter the original List rows output down to only the rows where the first column equals the current group name from the loop. That gives you the subset of rows that belong in the new file.
Then create a new Excel file in your destination folder and name it using the current group value. Since you want to overwrite files each run, you can just recreate them every time. After creating the file, add a table to it (Excel requires a table before you can insert rows). Once the table exists, loop through the filtered rows and insert them into the new file.
This pattern will create one file per group, overwrite them each run, and automatically handle new groups without any changes to the flow.
If you have specific questions as you build your flow, come back and post them to the forum.
-Mark