Filtering a subform by 2nd column in a combobox

[CJ_London]

A joining table won't work, some expenses cannot be split (e.g. a gardening expense for an entire complex)

if there are 10 apartments, divide the total by 10 or some other relevant factor such as floor area

 

[REZ]

How would I set this up so the user inputting the expense can just put it in once without seeing the joining table?

 

[CJ_London]

I don't know enough about how your business is organised but in principle you would use VBA code to execute an append query. But I would probably set up your property table to be self linking.e .g.

PK....PropertyName..........ParentFK
1......apartmentBlockA.......0
2......appt1..............................1
3......appt2..............................1
4......appt3..............................1
5......apartmentBlockB.......0
6.....appt1..............................5
7......appt4.............................1
8......appt2.............................5

the above represents apartmentBlockA having 4 apartments whilst apartmentBlockB has 2 and can be shown in a query by joining the table to itself on PK to parentFK.

So a charge for the whole block is assigned to PK=1 (or 5), and to individual apartments the relevant PK.

If the property setup is a group of properties that can be bought and sold, the table above would also need fields for bought and sold dates.

 

[REZ]

That is essentially what I tried to do with a Union query.
Thanks for your help. I'll try do it as a table instead.