This extension disables logging in for customers to a store, if their customer group is not enabled for that store under Store Settings -> Option -> Account -> Customer Groups.

*** UPDATE
Thanks for all the credit guys!

It took me very little time to create this; if you check out the content of this plugin, you'll find it's a pretty minor change to the login template files. Almost a bug fix to OpenCart I would say ;).

Due to this simplicity, this plugin is not capable of doing anything other than limiting store access to specific customer groups. I can not honor the many requests in the comments to add smart features, sorry!

Please develop: I am no longer an OpenCart user, so If you code and find this plugin doesn't work for a newer version of OpenCart, feel free to fix it (can't be too hard), release a new version and take all the credit ;).

*** END OF UPDATE

For single store installations, this extension allows you to easily restrict access to your store to specific customer groups.

For multi-store installations, this allows you to restrict the access of specific customer groups to just one, or a few of your stores. When customers use their account to login to a different store in your multistore set-up, they get a login error saying their account was not found.

- Allows a setup where one customer group has access to several stores, but not all of them (just check that customer group for every store they should have access to)
- Allows a setup where multiple customer groups have access to the same store (just check all these customer groups for that store)
- Allows you to combine these two setups in any way you want, for different subsets of customer groups and stores.

This gives you easy, powerful and flexible separation of your customer accounts between stores without having to drop your fancy multi-store installation :), and while keeping all features like different pricing for different customer groups intact.

Please, leave a comment for support. Your feedback is highly appreciated!