We are located in the Bay Area, California. The servers your website would use would be located in the USA. We have several web hosting packages to choose from, and you may start with a smaller package and upgrade as necessary as your website grows: https://www.ultimatewb.com/domain-names-web-hosting .
We are very open to adding features to our software, and have approved all customer feature requests as to date. We can add a groups feature to UltimateWB Full, whereby members can create groups for other members to join, to post and share - please outline which features you would need for this so we can review and confirm for you. (i.e.: members can create group, other members can join, may require admin to approve members, or open to membership, members can post in groups, members can post photos in groups, members can post events in groups, etc.).