Line a fine wire-mesh strainer with a coffee filter. Place strainer over a bowl. Spoon yogurt into strainer. Let stand 15 minutes. Spoon yogurt into a medium bowl, and discard strained liquid.
Pat bell peppers dry with paper towels. Stir peppers, feta cheese, chopped fresh dill, Greek seasoning, and garlic into yogurt. Cover and chill at least 1 hour. Store in an airtight container in refrigerator up to 3 days. Serve with pita chips.