According to this website it is possible to have a BLE master communicate with a large number of slaves Excerpt from web page
Many simultaneous connections – Bluetooth Smart has no defined limit on the number of simultaneous connections (trains) you can make. Perhaps we will find a limit someday, but for now it is safe to say you can use Bluetooth Smart to simultaneously run as many trains as you desire.
This is not the first time I have heard this capability mentioned but I have been unable to find any "how to" info even though I have made several web searches. It may well be that I don't know the correct terms to use in a search.
Perhaps someone here knows how to create links to multiple slaves or can post a link to a useful web site.