Investment account within my HSA account

Sherlock's suggestion Is the way I've handled this situation for years.  Accordingly, my Quicken file has 4 HSA Accounts: 2 Tax deferred Accounts that contain the "cash" component at HSA Bank, (my HSA and spouse's HSA), and 2 Tax deferred Accounts that contain the "securities" components at TDAmeritrade.

If your situation doesn't involve two distinct entities - HSA Bank and TDAmeritrade in my case - and everything is reported to you about HSA activity by one financial institution then you might be able to simply incorporate all your HSA activity into one Tax deferred Brokerage Account.