I have mailed BBCAN177 and asked about whitelisting list domains automatically and his response was whitelisting them would be unexpected behaviour for end users and I agree that it would be a bad thing.
He did suggest that theoretically as the whitelisting can now be done instantly that code to temporarily whitelist domains and then revert them afterwards could be possible at some point in the future.
Without knowledge of what blocking you have in place it's difficult to say what you could do reliably. If you're ok with web-based proxies then that is one option. That way pfBlocker would only see the request to the proxy domain, not the blocked domain which is either part of the URL or encrypted/obfuscated entirely.
For example I put a list I use into one proxy site and got this URL back…
https ://www.sitenameredacted.com/browse.php/jFq3YZ2gvRvXF3vBTEqKxhzEqhrhb9TNwIVIO6BD649KAQxY7W0fRByEs2TrB8Z5uRyDQTRJxht5weSttltrT64_3D/b29/fnorefer/
..so long as the proxy site is not blocked then your lists will be accessible to pfBlocker. Obviously you have to trust that proxy not to MITM your traffic or otherwise break stuff, which is why I've not included the name here.