If you can't remember speed dial numbers like me, you can try AContacts. It lets you add home screen shortcuts for all contacts, call log, organizations (not sure what this is, mine is blank, I assume it would be imported work contacts), and groups. So, with groups of 24-28 you can have one touch access to bring up a screen with all 24-28 (more requires scrolling) and then short or long press the contact icon to call (you have to set that option).