There are a few possible solutions available to you! The simplest would be to make use of our integration with Formstack which will allow you to have up to 3 unique sign up forms which can all direct to different Constant Contact lists. You can find more about Formstack Here.
The other alternative is quite a bit more complex, but also more powerful. This option is to use our API to create and integrate your own form. With this choice you have full control over the appearance and function of your form. However, this option also requires the resources to develop the form and connect it with Constant Contact. You can find more information on how to get started with our APIs here.