For 2-handed curtsey you could try to add two spheres, large enough not to 'slip' through the mesh of the skirt bur small enough not to show as a ball under the cloth, and then position them where you want the hand to grab the skirt. Then in simulation use the target tool to move the spheres to the hands. This should pull the cloth to the hand. Alternatively make the skirt a hybrid character with waist, hip and two 'arms' chind of hip to move the cloth. Let 'arms' each have one-facet geometry where you want to grab the skirt, rest of geometry is 'waist' and 'hip'. Make hip clothified body part. This should allow you to move the grip points as you like. All this not tested, sorry no access to system, but that is how you would go at this.