Hi there,
Reaching out to us on the Community is a great way to get your questions answered. I'm glad you've joined the conversation.
I see what you mean in regards to having multiple departments to run your business smoothly. At this time, when you send an invoice or estimate through QuickBooks Online, the customer's response will be routed to the email by which it was sent (the one that corresponds with the user who sent the email). I can appreciate that you'd like your sales team to be in charge of receiving email responses, however this is an arrangement you'd have to make outside of QuickBooks Online.
The workaround I'd suggest is to leave a memo note at the bottom of your invoice/estimate asking your customers to send any replies to an alternative email address associated with your sales team. To do that, simply write your message in the box called Memo at the bottom of the invoice/estimate creation screen. Alternatively, you can leave these instructions directly in the email by clicking the Customize option at the bottom of the invoice/estimate screen. Toggle over to the tab for Emails, then include these instructions in the box called Message to customer.
I think you raise an important point in having the option to receive emails to alternative email addresses. This would be a great addition to the product, and I'd be happy to submit this feedback on your behalf to the product engineers. You can also leave feedback from directly within your account by clicking the Gear icon > Feedback.
Let me know if you have any other questions for me. I'm here to help.
Have a fantastic week!