Bolt Circle Centerline through 2-points (180° apart)?

I have 2 holes that lie on a common bolt circle. The holes are 180° apart on the circle. Is there a way to create a bolt-circle centerline through these two points?

The options that I see are:

   Through 3 or More Points (but we only have 2 points...)

   Center Point

I can create a point, between the two hole centers, and then use the "Center Point" option - but the created point doesn't appear to be associatively linked to the two holes.

What is best-practice for creating a bolt-circle-ceterline through 2 holes that are located 180° apart on a common circle?

Thanks,

Steve