Another reply... Sorry lolhttps://goo.gl/images/TUfd1i
this is the Attached nest at the San Diego zoon I more or less got the idea from this and from my research on leaf cutters natural nesting habits. See each of those Chambers? Basically each one of those Chambers would dug out into brick and connected by the tubes.
Maybe it would be better to not add dirt at all? Or maybe just a small portion of it? Plus maybe I could cover the glass in red so that they don't see that as a place where light gets in and maybe they won't cover it?