How do I create a subset of contacts for emailing purposes

I have several contacts that I wish to mail to. Some have email addresses some do not; some emailable contacts I want to mail to and some I do not. I thought I would move the contacts off the cloud (as it would be faster to create and edit a subset). I then created a subset where an email address exists. However, when I delete a contact from the subset, it deletes it from the 'All contact' group. When the contacts were on the cloud, the system would prompt me, 'Do you wish to delete this card from the selected group or totally (or words to that effect)'. Now the system deletes the contact from the All contacts group (and this from the subset too). How can I get aropund this?