There was a thread a while back with somebody trying to figure internal paths to groups within databases in DT; I cannot for the life of me find it though. It wasn’t working as the user wanted anyway, and wasn’t looking for purely external paths IIRC… It is not recommended to alter the content of the database package directly. @chrillek posted a JS in 2020 which I think is aimed at doing what it is you are trying to do, though (that is, telling DT where to put the record).
The “intended” behaviour in DT3 is that files should arrive via the global inbox, though. From there DT can deal with the records using smart rules, moving that to other databases and/or groups automatically, as Hazel would. Hazel has a slightly more powerful set of rules; if you need those and therefore it is not an option for you to use smart rules in DT (unlikely…) then you have a few options:
- use a script such as the one @chrillek provided (but AS can do much the same)
- use Hazel to tag the files (e.g. Inbox2) and put them in the global inbox, and then use a smart rule in DT to move any records tagged that way to a destination of your choice in DT.