Yes, you can definitely build a system to automatically track and calculate the percentage of samples from the "reimbursement group" using the information you have in your database. Here's a general approach to accomplish this:

1. Identify the tables and fields: First, identify the relevant tables and fields in your database. You mentioned having a separate table for donors, so you'll need to identify the fields that indicate the group each donor belongs to. Additionally, you'll need to consider the table that contains the requestor information and the sample information, which should include the donor information for each sample.

2. Retrieve the data: Write a query to retrieve the necessary data from your database. You'll need to join the tables that contain donor information, requestor information, and sample information based on their respective keys or IDs. The query should fetch the required fields such as requestor name, sample ID, donor group, amount sent, and date sent.

3. Calculate the percentage: Once you have the counts, you can calculate the percentage using the formula: `(ReimbursementCount / TotalSampleCount) * 100`.

4. Display the result: Finally, you can display the calculated percentage in a desired format. For example, you could generate a report or output the result to a dashboard or user interface.

Remember to consider any updates to the data and ensure that the tracking system is regularly updated to reflect the current state of the database. This can be done by automating the process or integrating it with your existing data management workflows.

If you provide more specific information about your database schema and the programming language or tools you're using, I can provide a more detailed example or code snippet to help you get started.