What I propose would be something akin to having a pre-configured permission group setup for seasonal events.

Some examples would be and not limited to;

• Halloween
• Christmas
• New Years
• Easter

Plus many others. In the UK the Queens Birthday could be one such event.

These groups would be almost like /lp user/group <user|group> permission settemp except it wouldn't be a time set to expire - the time set would be when that group will be active between aa date and bb date.

Why don't you just add the group when aa occurs for a duration of bb - aa?

I don't see why this needs to be a special feature when it's easily do-able already.

i agree. just add a inherit from Halloween to your default group during the duration of the event.