Linq Query Help

This is a problem that has had me stumped for a few days, and countless searches have not lead me to a solution. This seems like a fairly basic technique, but I have had no luck with it, since I am not exactly a master using linq queries. Hopefully, this is presented in a way to clearly show what I'm after. I've chiseled-down the classes and code that I'm actually using, into a more simplified example so I can focus on the part of the solution that is causing me problems.

I am working on an older database application that uses .Net Web Forms, and the first step to a long process of revamping this application has lead me to a problem with Entity Framework 6. Actually, it's a problem with me not knowing how to do something in Entity Framework, more specifically, with a Linq query. I don't want to go too far into detail, so I'm simplifying a few of the Entity Diagrams here, then I'll ask for help in cracking the nut that I have been unable to crack.

Simplified Entities

The relationship is a one-to-many relationship between the Issues and Comments. One Issue can have many comments. My ultimate question is, how can I use a Linq query to come up with columns like this? The Comments Column is a concatenation of the CommentText Fields in each of the Comment Entities related to the Issue for each row.

Desired result

I can do this with SQL easy enough and concatenate the Comments into one column using a sub-query like so:

SQL Query with a sub-query for Comments

There are probably cleaner ways to get this done in SQL in more recent versions, but this is something I've been using since around 2007. I am considering using a Stored Procedure in my database, but I don't want to have these decisions made based on the fact that I don't know how to do something with one technology vs. the other.

Here is my attempt so far. I've created a C# class to act as a View Model

And here is part of the IssueFactory class and the function that will return the List of the IssueViewModel class. It seems like such a simple thing, and yet, here I am:

So that's it. Googling has gotten me nowhere with this for a few days. I thought I was going to be slick, and tried to call another function that I had created that built the bulleted list, but of course, linq queries can't call C# code like this, unfortunately.

So what's the piece of the puzzle that I have been missing? Anyone?

Thanks, in advance!