Xavier threw Yaxley a look. "Of course. Floo's the best way to keep an eye on things, so we'll have to switch over to that. Perhaps Anti-Apparation wards on the building to discourage that - with some exceptions. We've got some bright wizards in the building who can figure that out, I'm sure. Specific wards aren't all that difficult to produce."
He doodled on his paper as he thought. "We'll require everyone to use the Floo - though Flooing everyone in via the tellyphone booth would be impractical. Perhaps there's another way, with something similar. A marker of sorts, so we know who's coming in and when." Come to think of it ... "Think the Germans have something similar, actually. I'll see what we can do. The sooner the better on that score."