Amaryllis ... and How to Grow Them
Peggie Schulz (1954)
Amaryllis x Zephyranthes - "It is quite possible to pollinate amaryllis with pollen from zephyranthes. I have one lovely rose seedling to show from such a union. However, although I have repeatedly tried to cross them the other way, i.e., amaryllis pollen on zephyranthes, I have never been successful."

I haven't done this, myself.
Karl

Here is a link that might be useful: CybeRose & Bulbs