I'm pretty sure all the contacts will show up in Mail or other apps that offer you info from the Contacts app, but you can differentiate them when in the Contacts app itself.
If you tap on the Red bookmakr ribbon on the left page you'll be taken to the Groups and accounts page. If you do have more than one account set up to sync Contacts, you should be able to chose between them (for viewing purposes only) there.
If you don't see the ribbon, then you have neither contact groups, nor a second contact account synced.