Let's say I had a list of transactions with the buyer and the seller. People are often in both columns. I want to have one worksheet with information about the sales, and one about the purchases. However, I want to be able to pick a single name in the filter on the dashboard and have it bring up their sales in the one worksheet and purchases in the other. Is there a way to do this since they are different fields? (Just using the same values in a lot of cases)
I've just created a sample data to see whether I can replicate your question.
I'm sending you a link with my example https://public.tableau.com/views/Question/Dashboard?:embed=y&:display_count=yes
Sample data used:
+--------------+--------+--------+--------+
| Transactions | Buyer | Seller | Amount |
+--------------+--------+--------+--------+
| 123 | Matt | Jackie | 1000 |
| 456 | Jackie | Matt | 1500 |
| 587 | Phill | Jackie | 2000 |
| 874 | Matt | Phill | 1345 |
| 547 | Jackie | John | 1000 |
| 514 | John | Jackie | 1500 |
| 549 | Phill | Matt | 2000 |
| 451 | Jackie | John | 1345 |
| 159 | Matt | Joseph | 1000 |
| 457 | Jackie | Matt | 1500 |
| 114 | Joseph | Matt | 2000 |
+--------------+--------+--------+--------+
Steps:
I have called it "Parameter"
2- On "Buyer - Sample sheet" - Create a filter on the dimension Buyer.
Add dimension as filter --> Edit filter --> Condition ([Buyer] = [Parameter])
3- On "Seller - Sample sheet" - Create a filter on the dimension Seller.
Add dimention as filter --> Edit filter --> Condition ([Seller] = [Parameter])
4- On your dashboard
You will have Your seller sheet, the two sheets and the parameter. Every time You use the parameter, both sheets will change.
Hope you find it useful and it answers your question.