I would need to know if it's possible to include more than 2 profiles in a Contribution page, extending the core functionality. Does someone of you know whether there is any extension available that adds this feature? Thank you very much in advance.
i do not think this is available. It has come up for discussion several times. CiviEvents offers it and having the same for Contributions would be a good contribution but I gather it is a reasonable effort and no one has taken it on as a community project yet, or fundraised to get it built.