I love that you're getting use out of the Bank Feeds feature in QuickBooks Online. I can absolutely see how your bank merging with another group could cause an interruption in the automatic transaction downloads that you're used to. I'll walk you through how to work with the new merged bank.
There are a few things to consider with this process. The first is whether you have a new login URL for your bank. If there's not a new web address that you use to login outside of QuickBooks, you should be good to continue using the same feed connection. If there's a new web address, then it'll mean establishing that new connection.
If there's a new URL, you'll want to consider if you're going to keep tracking these transactions to the same account in your QuickBooks Online chart of accounts. If you don't want to use the same account in the chart of accounts, you can choose Link account in the bank feed and go through the steps to establish this new connection to a new account. If you do want to use the same account in the chart of accounts, first disconnect the existing feed so that you can connect the new feed to it afterward. Here's how you can disconnect.
Once you've done that, you can link the new web address to the account when you connect the bank. Here are the steps you can use to do that.
This will let us know that you're interested in QuickBooks Online being able to connect with that bank. There isn't a set timeline on when a bank will be added, however, so until it is, I recommend using the steps in the article Manually upload transactions into QuickBooks Online to continue working with bank transactions in the program.
I hope this has been helpful! Don't hesitate to ask more questions if you have any.