How can HTML be inserted from another file into a Jelly file?

[Moshe Cohen]

Hi,
I would like to display some HTML (within some boilerplate) that is generated as an artifact of my build.
So, I am looking for a way to insert the contents of such a file into the Jelly script on the fly - i.e. it is a different file on each build.
I have tried out Jelly core's <j:include> but that doesn't seem to work.

Any direction would be appreciated.

TIA