There isn't any guarantee but if you have a sales point of contact, you can get in touch with them to see if they can manage to make an exception and provide you with an invitation to the closed Alpha program. Otherwise, you can always get in touch with a sales person by filling out
this form.
Also, a necessary warning: if granted access it will be a good idea to use the feature in a sandbox environment only as Alpha features may contain heavy bugs and break your data.
Best of luck!