Contact network
A contact network is a group of people who can get in touch with each other quickly. No guarantee of help or friendship is implied. A power network or creative network is a contact network that collaborates on specific projects. A social network is always based on a contact network, but includes many more commitments - which almost always imply living close together. However, a contact or creative network can be global.
The Simple English article on 'contact network' has more detail.