Seeking a little advice on setup and configuration

This question is to all those hardened, experienced, Joomopilans out there.

I am setting up a website, community based of course, and am struggling on the best way to proceed. I have setup my main site, all be it with a lot more work to do. The basis of the site is to enable multi group participation and input.

My dilemma is wether to base everything on the main site and have menu links to components and modules, or to have subdomains for each group which then feed back info to the main site. The aim is not to end up duplicating data over several sites and to have access, were enabled, to all info when you are a member of multiple groups.

It looks like components such as jevents would work better from a central point. But Joomsport would possibly be easier to setup for each individual group on a subdomain as each sport has different configuration needs.

For example user1 might be a member of group 1, 3 & 5 for example. So I don't want that he/she should have to visit all these groups individually to access any information.

Both ways seem to have advantages.

I welcome any suggestions and sorry if I have posted this in the wrong section.
And hopefully you understand my dilemma from my brief description.

Many thanks in advance for those that take the time and trouble to read this and post back.

Joomla and extensions are designed to expect to be on a single domain. However, sub-domains can just point to Joomla menu links and you can have best of both worlds if you want custom domains for extensions. Setting up domain usages is going to be more complicated though.