I don't think I understand the priority part of the feature request, and perhaps not some of your terminology.
Adlists are blocks only - these are domains from public URLs that are added directly to the gravity list. Are you referring to enabling or disabling a specific adlist for a specific group?
Since adlists are for blocks only (they can't be used as whitelists), you can't add an adlist as a whitelist.
You can apply a domain entry to both the whitelist and blacklist and apply the domain to different groups. For example, if you want to add domain xxxyyy as a whitelist for one group and blacklist for another group, this is possible now.
Please provide additional description of what you want to do with the proposed feature.