Provide dynamic Forms Authentication Domain Value for session renewal

My project needs to support different set of domains, and uses FormsAutheticationTicket to create Forms Auth cookie upon user login, which works. But it has problem renewing Forms Auth cookie due to the way FormsAuthenticationModule renews its Forms Auth cookie. For example, if the domain of Forms Auth cookie is different from the current domain, additional forms auth cookie with the same name is created, resulting in renewal issue. Thus, I need a way to provide different Forms Authentication domain value dynamically, so that FormsAuthenticationModule can use it to reuse forms session cookie. Thus, the domain in the forms element below cannot be hardcoded.
<authentication mode="Forms"> <forms /> </authentication>        Question: Is it possible to provide domain value dynamically,  via `System.Configuration.Configur ...