I worked in one position for a year as a temp, then was hired on in that same
position and worked another year or so. I'm trying to cut space and was
wondering if one blurb could cover this experience. For instance, list total
time served, list company name something like "Company X/Employment Agency Y"
and a short line at the end of the blurb indicating the first year was through
the agency.

... or is this another example of dangerous territory?

As always, your insight is much appreciated.