Android version of iGap has a feature to create channels in private or public. You can create channels and add members or they join themselves in order to benefit the shared media by you. It helps you to share any files or news you like to with anyone whether you wanted to add or s/he added by the link.
In iGap app you are able to have groups in public as well. As it is assumed in public groups, a community of users can come together in a group and chat with each other. But if you want to have a group in private and do not make any unknown member enter your friendly community, convert your public group to a private.