Copy and paste the following into the "config/interiors.lua" file. You may want to add specific shells to the different "small", "medium" or "big" sections. They are separated by type below.
Copy {model = 'bk_apartmentone', label = 'DC Apartment 1', offset = vector3(1.540771, -2.907349, -0.363182)},
{model = 'bk_apartmenttwo', label = 'DC Apartment 2', offset = vector3(-7.216675, -0.770630, -0.364571)},
{model = 'dc_apartmentthree', label = 'DC Apartment 3', offset = vector3(1.931152, -5.933044, -0.355030)},
{model = 'dc_apartmentfour', label = 'DC Apartment 4', offset = vector3(-1.951172, -6.115295, -0.439957)},
{model = 'bk_houseone', label = 'DC House 1', offset = vector3(3.395996, -3.424683, -2.146027)},
{model = 'dc_housetwoshell', label = 'DC House 2', offset = vector3(0.893555, -6.557922, -1.797283)},
{model = 'dc_housethree', label = 'DC House 3', offset = vector3(-8.373047, -2.479431, -0.497375)},
{model = 'dc_housefour', label = 'DC House 4', offset = vector3(8.334991, 4.599335, -1.882324)},
{model = 'dc_housefive', label = 'DC House 5', offset = vector3(5.621460, -2.730499, -0.123283)},
{model = 'dc_housesix', label = 'DC House 6', offset = vector3(-4.257080, 13.136597, -1.848206)},
{model = 'dc_houseseven', label = 'DC House 7', offset = vector3(0.608521, 1.784790, -0.451202)},
{model = 'dc_trapshellone', label = 'DC Trap 1', offset = vector3(0.246094, 3.146912, -0.238735)},
{model = 'dc_trapshelltwo', label = 'DC Trap 2', offset = vector3(1.418213, 3.788696, -0.265732)},
{model = 'dc_trapshellthree', label = 'DC Trap 3', offset = vector3(-0.000122, -6.097412, -0.837967)},
{model = 'dchotel_shell', label = 'DC Hotel Shell', offset = vector3(0.040527, 4.387962, -0.403328)},
{model = 'dc_townhouseone', label = 'DC Townhouse One (Dirty)', offset = vector3(3.735229, -5.845581, -1.967209)},