© 2020 IEEE.Group decision making (GDM) approaches have been very popular which helps to choose the most appropriate option from an alternative set. GDM has been applied in environments, where the group of people is involved to make a decision on cases. In online social networks (OSNs), GDM is a need especially in a content of data sharing process where the content of the data has multiple users' information on. That type of data is called co-owned data. In OSNs, social network group decision making (SNGDM) is an approach which is used to prevent privacy leakage when co-owned data are shared. This is because some OSNs' users might get quit from an OSN platform because of the privacy issues, or they might become unfriend with the user who causes the privacy problemApplication of having group decision making in OSNs' platforms has a challenge. The challenging part of SNGDM process is to weight users' opinions on their choices on the alternative. One way to weight group members' opinion is to use users' trust values. In this paper, we propose an approach where the trust values are used to weight decision-makers' opinions on a co-owned data sharing process in OSNs. The trust values are used as weight vectors in the Extended Induced Ordered Weighted Average (EIOWA) group decision making technique.