FTX.US has Subaccounts to allow you to split up your positions
To manage your Subaccounts, go to https://ftx.us/subaccounts. If you are already on the website, click the settings icon in the top right corner, then select subaccounts in the menu bar on the left.
There you can create new Subaccounts, switch between which Subaccount you're using, and transfer funds between Subaccounts. You can also change which Subaccount you're currently using by clicking on the toggle buttons under "Select Account."
When using a Subaccount, you can only trade with funds that have been moved to it. That means you can only trade on spot markets or convert using funds in the Subaccount.
Subaccounts are useful if you want to separate different strategies or traders; or if you want to isolate a particular position from the rest of your book.