(1) for the joint ownership of any one or more facilities or improvements which they have authority by law to own individually;
(2) for the joint operation of any one or more facilities or improvements which they have authority by law to operate individually;
(3) for the joint acquisition by gift, grant, purchase, construction, condemnation or otherwise of any one or more such facilities or improvements and for the extension, repair or improvement thereof;
(4) for the exercise by an interlocal entity of its powers with respect to any one or more facilities or improvements and the extensions, repairs, or improvements of them; or
(5) any combination of the foregoing.