multiuser
adjective
mul·ti·us·er ˌməl-tī-ˈyü-zər 
-tē-,
-ti-
: able to be used by more than one person simultaneously
Example Sentences
Recent Examples on the Web CommunitySocial networks and wikis that have quickly developed an extraordinarily active multiuser community and an exceptional following of users who assist with content development. 
Michael Calore, WIRED, 14 Mar. 2010
Michael Calore, WIRED, 14 Mar. 2010 Word History
First Known Use
1964, in the meaning defined above