Well you can have multiple fathers but you cant get combos like that from 2 different fathers. For instance..
normal to a spider gives you normals and spiders.
normal to a spider dad and a pastel dad could give you normals, spiders and pastels but you wouldnt get any bumblebees. The fathers genes can only combine with the mothers. Not another fathers. Make sense? 2 sperm cant combine. lol! Sperm can only combine with the females egg. BUT, it is possible for 2 sperm from 2 different fathers to get into the same egg at the same time. You could possibly have an egg with twins that have different fathers. their genes would not combine though.