Displaying Related Documents in a Text/XML Transform

I am trying to link the related documents for a page inside a Text/XML transformation and the following pretty much takes care of it:

{% DocumentContext.CurrentDocument.RelatedDocuments.All.ApplyTransformation("Abstract.RelatedDocuments") #%}

The only problem is that it includes both left and right relationships and I only want to list the ones where the current document is the left page of the relationship. Is there anyway to pull that list using a macro expression?

Also I know the docs show how to do this kind of thing using an ascx transform but I wanted to see if I could figure it out using a Text/XML transform and am hoping someone can point me in the right direction to get it finished off.