There is a distinction between a joint venture, where all members are responsible for generating their own profits and where securities compliance is not required, and a passive investment (otherwise known as an “Investment Contract”), where investors are relying on you to make a profit on their behalf. The latter is a “security” and compliance with securities laws is required.
If you are selling securities, you either need to register your offering (i.e., go public — a long and expensive process) or find an exemption from registration, such as Regulation D, Rule 506, or another applicable exemption that will allow passive investors to legally invest with you without registration. There are several choices and there are securities exemptions that will allow unaccredited investors to invest with you.
So, in answer to your question, both scenarios could be group investments, but both are not securities. A securities attorney can help you determine the appropriate structure (JV or Syndicate) based on your facts and circumstances and then draft the appropriate legal documents.