NodeJS/Mongoose - Combining then accessing collections - node.js

Question

I have a field called 'allGroups' under my Blogs schema which combines all the options from 3 different models (Community, Business and Help) and allows the user to select multiple options from a dropdown list and store their ID in an array.
allGroups: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Community"
},
{
type: mongoose.Schema.Types.ObjectId,
ref: "Business"
},
{
type: mongoose.Schema.Types.ObjectId,
ref: "Help"
}
],
This is correctly saving the id of the respective option to the database; however, when I try to retrieve the name of each in my .EJS template using a forEach loop, I'm only able to return group._id, whereas I also want to return group.name (all individual models have the 'name' field). So my first question is, do I need to add something else in my model for the allGroups field to be able to access group.name, or is there another way I can access?
<% blog.allGroups.forEach((group) => { %>
<div><%- group._id %> <%- group.name %></div>
<% }) %>
Second question: As well as returning group.name, I also want to link to the respective records, which requires me to access their original models. Below is some mock code as an example; how can I reference the original model that each record belongs to so I can return the correct link prefix for each? I'm aware of Mongoose' 'instanceof' method, but I've only managed to get this to work in my controller, I'm unsure if it's possible to use within my .EJS template directly? Or is there another/better way to do this? Thanks.
<% blog.allGroups.forEach((group) => { %>
<% if (Original Model === "Business") { %>
<div><%- group.name %></div>
<% else if (Original Model === "Help") { %>
<div><%- group.name %></div>
<% else if (Original Model === "Community") { %>
<div><%- group.name %></div>
<% } %>
<% }) %>
Current controller for reference:
async blogShow (req, res, next) {
let blog = await blog.findById(req.params.id).populate('interviewees allGroups likes').populate({
path: "comments",
model: "Comment",
options: { sort: { createdAt: -1 }}
});
res.render("blogViews/showBlog", { blog, cloudinary });
},

Answer 1

You have to render the ejs file here res.render("blogViews/showKnowPangyao" it should be something like blog.ejs or blog:the name of the ejs file, and in place of knowPangyaoyou have to pass the results returned by query that is blog not {knowPangyao, cloudinary } it should be { blog:blog }.
TRY:
async blogShow (req, res, next) {
let blog = await blog.findById(req.params.id).populate('interviewees allGroups likes').populate({
path: "comments",
model: "Comment",
options: { sort: { createdAt: -1 }}
});
res.render("blogViews.ejs", { blog:blog });
},