Negative. You'll need a subscription for each device.
The only work around would be is if you could have the MAC addresses the same, and never use the other 2 devices at the same time. Easy for Kodi, but not so for other devices. Only other option would be to swap MAC addresses online (for instance with NFPS) to activate the other devices.
Again, can't use more than one at the same time either way you cut it unfortunately, so it adds $$$ up pretty quickly if you don't make a bulk purchase all at once for 3 subscriptions.
"1 Sub = 1 MAC" is how I saw it concisely put.
With that said, even with a shit currency conversion, I'm glad I jumped on board and got this going.
Sorry m8,
-D