It is possible to connect to several Android HotSpots at the same time ?
You cannot connect your android to two wireless connection at a time, as of now. You can do so in your PC or Mac using USB WiFi Adapter.
But if you have mobile internet and a WiFi connection, you can combine both using an app called VideoBee. But as the name suggests, this app is only meant for streaming videos. Learn more about VideoBee here
Hope this helps.