When adding a database field of type "database", can it be specified to only show records from within a specific category of the other database?

Let's say, for example, that you have a database of Vehicles (DB A) and with that database you have Vehicle Types as a category (eg: "truck", "sedan", "convertible", and so on).  You can then add records for different vehicles and categorize them by body type.  You now want to create a second database of Vehicle Parts (DB B) and you want to have a field that displays which vehicle the part is for so you can create a field type of "database" in DB B (Vehicle Parts) pointing over to DB A (Vehicles).  That works perfectly and you end up with a nice organized record that automatically links the vehicle part field to the record in DB A.  But the part is meant only for convertible vehicles; no reason have all of the DB A (Vehicles) records available for selection if only a small subset is applicable.  With the field in DB B (Vehicle Parts) pointing to DB A (Vehicles), is it possible to restrict the results to be within a specific category (Vehicle Type) of DB A (Vehicles)? 

 

That’s not possible. 

13 minutes ago, opentype said:

That’s not possible. 

Thanks for confirming. :)  If I was able to specify a category it would've really made my life easier when creating several databases that can be potentially linked to each other (it actually would've reduced the number of databases I'd need to create for what I'm envisioning).