A SendBoard account is always linked to a single Trello workspace. You can add the Power-Up to multiple boards within one workspace and they will all be linked to the same SendBoard account.
Add the Power-Up (again)
Many teams use separate Trello boards to collaborate around different areas of work - accounts, support, sales etc. You can use Email for Trello in the same way. Simply add the Email for Trello Power-Up to each board you wish to send and receive emails on.
Once added, you will be prompted to set up the mailbox for that board.
Use a different email address for each board
You can set up a different custom domain for each board. The DNS settings will be unique for each domain, but the steps for setting up the DNS records (DKIM & Return-Path) will be the same. For example:
Any email you send from Trello would have the reply-to address set to the custom email address of the board you send from.
Or use the same email address on multiple boards
Although every Trello Board has a unique SendBoard address, you could choose to use the same Custom Email Address on multiple boards.
With this type of setup, you could choose which board new emails should arrive on. Depending on how you set up your forwarding rules, new emails could arrive on either Board-A or Board-B (Or both). Any emails you send from Trello would have the reply-to address set to email@example.com, regardless of which board.
You could also set up advanced forwarding filters with your email provider to route incoming emails to different boards depending on the subject or email address of the incoming email for example.
Move cards between boards
As long as both boards have the Email for Trello Power-Up active, you can move cards between boards while continuing with email discussions. Emails will be sent from whichever email address is configured on the board the card is on. Replies will always be attached to the correct card.
Tip: Use Trello Automation to automatically move cards between boards based on certain triggers. For example, when a a card is due or when a card is moved to a certain list. You can easily link multiple Trello boards with this neat trick.
Replies will always be attached to the correct card
Replies will always stay attached to the correct card, irrespective of which board it is on or how your forwarding rules are configured.
If you send an email from Board-B, but your forwarding rules send the reply to Board-A, Email for Trello will automatically detect that the related card is on Board-B and attach the reply to the original card.