Multiple Summoner is a program that allows you to generate commands to summon multiple entities from one command block! Add in any entity, specify properties and change how many of each you want to summon with each execution.

The program lets you load and save command files, so you can come back and edit a command you've created later. It suggests different properties for you as you type them in. You can change the entities and the location (XYZ) that the command will spawn them at. When you input the given command into a command block, it will summon all the given entities in one place! You can then use the /spreadplayers command, if you like, to spread them out randomly.

IMPORTANT NOTE: Windows 8 or other operating systems may prompt you that the application came from an unknown location or is unsigned. Do not worry about this, it is simply because I don't currently have a Windows Developer Certificate, so Windows does not recognise my programs as any specific publisher (it does cost £100 to get a certificate and all...)