Hi becausenoone ,
In general, there's no way to send the same survey unique link to multiple email addresses within Qualtrics. Your best option is to export the links and distribute them via an external email solution.
If you are looking to have the alternate email address available in the Distribution History, you could assign those emails to the External Data Reference field; that's the closest to Embedded Data that you can get.

Hello Matthew,
thank you very much for your answer. Indeed the External Data Reference field solves my problem because it helps me identify which survey was sent to whom about which topic. The next step for me is to use xlookup in excel to pull out the individual survey links.
However, when trying to send the email to the managers, I noticed that I can't send the email invitation from the project view without adding the "Link" field (it forces me to add the "Link"). I would actually need in this message the link from the original distribution (the one sent to the original recipients that I can pull from the original distribution history). Is there a way to send it without the "Link" field? I googled that I can do it from the Directories->Distributions->Send emails without a survey, but in there when I try to choose a library message, no messages appear even though in my own library I have a template message (type: email invite). I tried copying it in various types, e.g. general message etc., but nothing worked. Do you have any idea how I could have library messages working from the Directories Distributions view? Or even better, is it possible to send the message without the "Link" from the project distributions view instead of the directories distribution view?

I've only done it a couple of times before, but you should be able to save a copy of an Invite as a General Message and send it through the Directories Distribution without a survey link. If you've made a copy of your Invite and saved it as a General Message, but you can't find it when you set up your Directories Distribution, make sure you're looking in the right Library and folder.
Alternatively, you could just copy the original message (either from the editor or in the HTML window) and paste it into the message editor window in your Directories Distribution.
It's not possible to send a message without a link from the project distributions view. The best you can do is to make the survey URL hard to find in the body of the message.

Hello!
If you'd like to notify the manager only once the main recipients have responded, you can set up an email trigger based on "survey submitted" and then have an automated email trigger go to the manager saying "the main contact have submitted a survey" (and include the survey details if you want).
This would require the manager email be added as embedded data to the original target list you upload upon the send of the survey invite email so you can reference it when setting up the trigger.
Perhaps a working workaround :)
All the best
-Mattias

Hello MatthewM ,
thank you for replying again. I have my messages saved in the message library, as shown in the screenshot. Is this where I should be looking? Or is there some other library elsewhere?
If my templates don't work, I will use the workaround with just copying my message. As for sending the invitation with a hidden link, unfortunately this is risky because Qualtrics doesn't allow me to hide the link - even if I change the CSS coding to display:none or if I try to format it as white. The link remains very visible with blue and underscored formatting and I am afraid my recipients may enter think link instead of the intended link.
MattiasM , thanks for replying. This solution unfortunately won't work for me, because I need managers to follow up with the main recipients to encourage them to fill out (not to follow up on a submitted response).

What's the name of the message you're trying to load into your distribution? Is it the message that appears in your screen shot, or is it outside of the snip?

Hello MatthewM ,
below I am sharing the screenshot of the messages I have in mind. I have both email invite version and a general version, none of which appear when trying to load them in the distributions view.
Also sharing a snippet of my library looking empty when I try to load a message from the distributions view (I removed from the screenshot any identifying information, hence some blank spots):

Sorry for delayed reply, I was on vacation. This is tough to troubleshoot without access to your account. I can't see the name of the library the messages are saved to in your first screen shot, and it looks like there are two libraries whose names are obscured in the second screen shot. If you haven't done so already, I would suggest checking the other libraries in the second screen shot to rule out that the messages weren't saved there somehow. If you don't find them there, I would recommend contacting Qualtrics support.

Hello MatthewM ,
thank you for replying and I hope you had a good vacation.
I obscured the name of the libraries because they contain my name and surname and the name of my company. All libraries that appear there are empty. Looks like indeed it could be a bug, so I will contact Qualtrics support.
Thank you for all the help!