Colloidal microcontainers, such as hollow capsules and colloidosomes, have a range of applications, including drug delivery, energy storage, and artificial protocells. In this study, we present a versatile and scalable self-assembly approach for encapsulating cargo particles within well-defined porous membranes or cages. The encapsulation process involves camouflaging cargo within a liquid matrix that serves as a scaffold for satellite particles to form densely packed shells around. These satellites fuse to create self-standing cages, after which the liquid matrix is dissolved, trapping the cargo inside. By adjusting the fusion protocol, we can control the porosity of the cages at various length scales. We demonstrate the potential of this technique by employing functional cargo to showcase transmembrane transport phenomena, such as the delivery and active uptake of nanoparticles.