You can easily set up as many different groups as you want in iCloud, and have them synced to all devices. Contacts from group A would never know about any other contacts from other groups, unless you wanted them to know etc.
Go to the phone app, clic on Groups, and you would see all the groups you have created in iCloud. If you want to only see a specific group to check for a certain person, make sure that only that group is ticked and then click done. That will show you only the contacts in that group. Makes it easy to find people while also keeping business contacts separate from private.
No need download an app for what can be done in iCloud, in my opinion.
