Create your text. Kern. And so on.
Type > Create Outlines.
Object > Path > Release Compound Path. This will fill in all the counters. Do not fear, young padawan. We shall preserve counters, albeit in a crude fashion. See Step 5.
Once the compound path is released, the text is effectively ungrouped, letter by letter.
To get counters back, select a single letter and its interior path by dragging a selection rectangle (just use the Direct Selection tool) around it. Go to Pathfinder > Exclude Overlap. Rinse, repeat, for each letter with a filled counter.