You are referring to the form-properties I presume? It's currently not possible to define a "shared" set of form-properties for multiple user-tasks. Are you using a custom UI to show the forms? If so, you can opt for NOT using the form-properties but count on the "form key" instead, creating a form in your UI and passing in variables when submitting the form, instead of using form-properties.
This way, the way the form is rendered is completely up to you, so it can be dynamic/shared with other user-taks, while the process is unaware of this, and is just receiving variables.