Product Parent(s) in Product XML Feed?

What Web part are you using? I assume Hierarchy Viewer, but i want to verify.

You can set the Path for most repeaters to be a parent path a couple ways:

1: Use the {#} in the Path to get the path at certain levels, ex: /{0}/{1}/% would select the /FirstLevel/SecondLevel node alias path.

2: Use macros to get the parent/grandparent's NodeAliasPath of the current document (I think {% DocumentContext.CurrentDocument.Parent.Parent.NodeAliasPath |(identity)GlobalAdministrator%} , but try that)

3: A buddy used a Macro DataSource to load in the Documents in the Path of the current document and repeated that, i would have to look at what the specific macro context was though.

I'm using the Kentico Products RSS Feed webpart (as mentioned above). Your first method doesn't help, as I have no issue going through the tree. Your second method won't work because the feed itself is located in a different directory than the products themselves, so the CurrentDocument is the page I'm on, not the product page that I want to retrieve. What I'm trying to get is <productGroup> in the following transformation, where <productGroup> is the page name of the parent of the product page in question.

<Product>
    <Country code="US">
        <manufacturerName><%# CMS.Helpers.URLHelper.URLEncode(CMS.SiteProvider.SiteContext.CurrentSite.DisplayName.ToString()) %></manufacturerName>
        <sku><%# Eval("SKUNumber") %></sku>
        <alternateSkus>
            <%# IfEmpty(Eval("SKUNumberAlternate"),"","<altSku>" + Eval("SKUNumberAlternate").ToString().Replace(System.Environment.NewLine,"</altSku><altSku>") + "</altSku>") %>
        </alternateSkus>
        <model><%# EvalCDATA("SKUName") %></model>
        <productName><%# EvalCDATA("SKUDescriptiveName") %></productName>
        <upc><%# Eval("SKUUPC") %></upc>
        <releaseDate></releaseDate>
        <productPageUrl><![CDATA[<%# GetAbsoluteUrl(GetProductUrlForFeed(Eval("SKUGUID"),Eval("SKUName"),Eval<int>("NodeSiteID")),Eval<int>("NodeSiteID")) %>]]></productPageUrl>
        <imageUrl><![CDATA[<%# GetAbsoluteUrl(GetSKUImageUrl(720)) %>]]></imageUrl>
        <productGroup></productGroup>
        <category></category>
    </Country>
</Product>

Is there not a value from the RSS feed that contains that item's document id (or better yet, node id)?

If there is you can use <%# CMS.DocumentEngine.DocumentHelper.GetDocument(Eval<int>("TheDocumentID"), new CMS.DocumentEngine.TreeProvider()).Parent %>

Or if node id

<%# CMS.DocumentEngine.TreeHelper.SelectSingleNode(Eval<int>("TheNodeID")).Parent %>

Note that when calling the nodes/documents this way, it often will only get the Document/Node fields, once you get the parent's document ID you may need to call the below to access fields that are not universal to all pages.

<%# CMS.DocumentEngine.DocumentHelper.GetDocuments("My.Class").Where("DocumentID = "+ParentDocumentID).FirstObject.GetValue("TheValue") %>

Lastly, if you add this to the top of your transformation, you can cut out the "CMS.DocumentEngine" from each of the calls, makes it cleaner

<%@ Register Namespace="CMS.DocumentEngine" %>

<%# DocumentHelper.GetDocument(Eval<int>("TheDocumentID"), new TreeProvider()).Parent %>
<%# TreeHelper.SelectSingleNode(Eval<int>("TheNodeID")).Parent %>
<%# DocumentHelper.GetDocuments("My.Class").Where("DocumentID = "+ParentDocumentID).FirstObject.GetValue("TheValue") %>

I'm not sure I can get a node or document ID. Being that I'm working with the e-commerce module, I have both an auto-generated SKUID and a ProductID for the page, but both values return null when passed as an ID to the GetDocument method. I'm pretty sure I can't get the node ID, but that would definitely solve the issue if I could.

You will have to get the Document/NodeID from the SKUID

At this point i would highly recommend adding a custom transformation method that will take your SkuID and give you the NodeID, it can be done in the transformation but it's going to be messy, but try this:

<%# CMS.DocumentEngine.TreeHelper.SelectNodes("/%", true, where: "SkuID = "+Eval<int>("SkuID")).FirstOrDefault().Parent %>