Thanks for the suggestion. I figured out another work around:

I made only one caption: Figure 3. Then the 'a' became part of the blurb.

Then for figures 3b and 3c, I made them pure references to "Figure 3" with 'b' and 'c' tacked on just to the right of the reference.

This makes sense because if ever "Figure 3" has to change, figures 3b and 3c will change accordingly. Likewise, any inline references to figure 3 (with 'a', 'b', or 'c' tacked on just outside the reference) will also change accordingly.