In a pestle and mortar mix the ingredients and grate the nutmeg into it
Then smash together to makes a grainy powder
Some bits of the clove you may not be able to grind fine, I wouldn't worry about it unless you want a fine powder then the smallest attachment on your mixer. I have an Indian mixer which I use for my coconut chutneys and it has 3 jars I used the one with 3 blades. Or else just use the pestle and mortar it should work.
Store away the remaining homemade allspice replacement powder in a tiny airtight container