There are, of course, guides on how to get your amaryllis to bloom in December (scroll halfway down here, for example). Alternatively, you can put your amaryllises on a neglected windowsill in the spring and pretty much forget about them. Then they’ll bloom when they feel like it. Like in August.
I have a total of four amaryllises and I doubt I’d get as much enjoyment out of them if they bloomed all at once as I do now. Whoever blooms gets to be queen of the dinner table and admired at every meal and whenever I walk into the kitchen. One might even do so at Christmas.