Preheat oven to 400℉. Roast eggplants whole on a large baking sheet for 1 hour, turning once. On the same baking sheet, cut 1 bulb of garlic in half and drizzle with olive oil. Remove the garlic after about 30 minutes when it starts to brown.
Once the eggplant is cooled, cut in half vertically and scoop out the insides. Place the eggplant in the bowl of a food processor. Squeeze the garlic into the food processor.
Add the olive oil, lemon juice, salt, pepper, crushed red pepper, and oregano. Process until smooth.
Pour into a serving bowl and drizzle with more olive oil, add olives, crumbled feta cheese, and more oregano and crushed red pepper.
Serve with warmed pita chips.