You can in the new version (3.0). You need to get 200 gems, pay them to the orc girl and that will unlock the camp area. There you can put tents (bought at the slaver which is a new location available on the dungeon selection map after you level up your dungeon a few times) and as long as there are enough tents girls will move in. There's a single "captured" girl in every adventure that'll request to join you as long as you finished this adventure without falling to 0 hp (doesn't matter if you told her to come with you or not). You can also capture hostile girls; for that you need to raise their relationships to "loves" (just finger them for, like, 10 real-time minutes...) and then tell them to join your camp. If everything is ok they will say yeah and your game will autosave. They don't get to keep their battle modifiers though...