Concrete5 is an excellent CMS for company websites, it has a _long_ list of built in features, but can also be extended in a really clean way. We've used it for many company and organisation sites and it's been great to have the level of control we've had, especially in terms of fine-grained permissions on content. We've converted quite a number of corporate websites away from Wordpress and other CMSes to concrete5, and we've ended up with very happy clients, and it works great to manage ongoing requests and changes.

In terms of your specific question, it is possible to have concrete5 set up where you have one main site, but then multiple parts of the site's tree configured with separate themes and content. For version 8 of concrete5 there is an official add-on available that allows you to directly map domains to specific parts of the sitemap, effectively creating mini-sites controlled by the same installation:https://www.concrete5.org/marketplace/addons/domain-mapper...

Another options is that at a server level you just map a domain to redirect to specific URL on your main site. It depends on how separate you want the domains/website to appear.

The upcoming version of concrete5, version 9, is planned to have multiple site management directly built in, where it better handles some of the other multi-site considerations like shared files. There's still some time before version 9 is released, but depending on your project timeline it's something to keep an eye on.

I'd suggest it does come down to how many mini sites you are planning to have, and how they need to work together. If the subsidiary websites really don't share much in the way of files or users, you might find it's simply easier to have multiple concrete5 sites set up. We've built quite a number of websites for organisations where they've had their 'main' site, but then off-shoot projects and departments. We've found that only a few cases we've wanted everything managed by the same install, and it's been actually easier to manage them longer term as actual separate websites.

And in terms of ecommerce, there are a number of options available. There are marketplace options available, Stripe, Paypal, Snipcart, etc, as well as an open source project called Community Store (https://github.com/concrete5-community-store), which a full shopping cart with support for quite a number of payment gateways. There are also other ways to integrate eCommerce like doing a Shopify integration. It all comes down to your specific needs and what you are wanting to achieve - there are ways to handle basic payments (i.e. clients paying invoices, all the way up to fully customised shopping carts).

You're welcome to send me an email at ryan@mesuva.co.uk if you're wanting to further discuss your needs, or you could continue to outline what you are looking to do here.

Myself and others in the community are happy to both offer general advice with concrete5, as well as offer professional development services - there's a really established community in that regard.

Cheers
-Ryan

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