ok... if your using unity, why bother with construct 2?
granted, im using construct 2 caus its easier to make sprites so i digress
you can have the hit box using the bottom icon on the sprite art image (not for the tiled background)
also you can edit this to have an auto detect hitbox on the properties for the sprite (so circles)
you cannot have multiple hitboxes on one sprite, but you can have several sprites pinned together with hitboxes in different places
hope i understood your question correctly... i have no idea what a smtelse is