Head to your portfolio screen. (Click to zoom image)
Select the portfolio in which you wish to filter transactions in and then chose the "Transactions" tab.
Click on the blue filter icon on this page and a large menu of filter options will pop up.
Filter out an exchange by selecting "Select None" on the Account Connections line.
Now select the "Select or View" button adjacent on the same Account Connections line.
All the exchanges and accounts are now deselected. When filtering transactions by account connection, you can select one to see all the transactions coming only from that one account or you can select multiple account connections to see the tied transactions. In this example, we are selecting only one account connection to filter transactions.
Click the "Go Back" button on the top right corner of the menu.
Click on the blue "Apply" button on the bottom right corner of the menu and your transactions are now filtered.