I cannot stress enough my neverending disappointment with the useless support answers provided here. The only actual answers I've ever gotten are from other users. The QB might as well not show up.

Since the OP ACTUALLY SPECIFIED that they were using Chase I can tell that I have done what they proposed and it works great.

I made a new CC account "Chase Master".

I moved my existing account to be a subaccount of Chase Master (this did not break the bank sync for this account).
I then created a new CC account for each of my employee cards, all as sub-accounts of "Chase Master".
I then went to "Bank Transactions" and clicked on the drop down next to "Link account" and chose Manage Connections.

(side note) When I first linked my Chase account, I selected "link all accounts". If you didn't do that you may have to start the process over.

Now in this list under Chase were all of my employee accounts.

I selected one, chose to link it, selected the new sub-account as the link.

I repeated this for all employees.
This did not mess up my previous (15 years) of reconciliation on the original account and all new reconciliations on the master account include the charges for all sub accounts.

Really QB support, would it have been so hard for you to just say that all those years ago? It's just sad.