Currently there is no way to implement a form at project level...forms can be implemented at the package level only.
For forms for certain package(s) of some specific project, the form access will be on the form type level, not at the form level. In other words, for example, if you set update access for "Developers" for form type "Q and A", then ALL forms that have type "Q and A" will be updated by "Developers" group users--this means if another project package has this kind of form, that form in that project package will be updated by "Developers" users only, which may not be what you want.
The only "workaround" we can think of is to create a custom form type and use the custom form type for form(s) for the specific project only. This way, you can configure which group(s) can update the form(s) of packages of this project.