I need to send an e-mail to each user in different Custom Fields once a transition happens (some reviewers), is there any way to make this happen without having to pay for an add-on? I know I can do so paying for them.
You could fire a generic event (i don't know if you are familiar with this) on a particular transition.
You have to create a new event which will be set as a post function on the transition. Then, you will have to edit your notification scheme, and specifically the new event created by adding your Custom field as Recipient.
I can describe it more precisely if it is not clear.
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