Yes - A site can be part of more than one portfolio (or subgroup) in Measurabl. There are a couple of ways that this is possible in the app.
You can have a site that is part of a portfolio, and is also part of any subgroups or funds created within that portfolio. Note that subgroups or funds are created as a way to classify a piece of the portfolio by similar characteristics such as size, location, property type, etc. When a subgroup is created and a building is added to that subgroup then that site lives in both the large group (which contains all of the portfolio’s sites), as well as in the smaller subgroup (commonly known as a “fund”). In this case, all utility and non-utility data will stay the same for that building across its multiple groups.
You can also share an ENERGY STAR property into two different portfolios in Measurabl. Please see the section 'What if I want to share a property(s) between two Measurabl portfolios?' in the FAQ section of this article.