Recommendations for Membership Session Management

What products are recommended for managing the number of sessions a user can have open simultaneously? We are using the Membership plug-in and don't see anything to control illegal sharing of account information.

Specifically, we want to limit the number of logins within a fixed amount of time to a limited number of i.p.s to avoid theft of content. I know this is not a perfect world but it is good enough for our purposes. If there are other recommendations to achieve the same purpose, we are definitely open to them.

I know can write some session management stuff in PHP and create associated database tables to do this but I am looking to see whether some recommended products exist to determine whether it is worth my time to do so.

Thanks!