Help to show dropdown list

[deltai]

Friends,

New doubt about dropdown list, between 2 related tables.

Have table DB_PATRIMÔNIO (patrimony) 

and table DB_EMPRESTIMO (loan)

That last have field [ID_PATRIMONIO] is related.

I want drowpdown use this conditions to show information:

1- DB_PATRIMONIO[CONDICAO]="EM USO"
2- if DB_EMPRESTIMO[ID_PATRIMONIO] (related field) not exist in this table, what patrimony can only be borrowed once
3- DB_EMPRESTIMO[SITUAÇÃO]<>"ATIVO"

After several attempt i do it just like this, filtering only table DB_PATRIMONIO and no sucess to filter together table DB_EMPRESTIMOS.

This way it partially works: FILTER("DB_PATRIMONIO", [CONDICAO]="EM USO")

But I want something like this:

FILTER("DB_PATRIMONIO",
              AND(
                         ([CONDICAO]="EM USO"),
                         (SITUAÇÃO<>"ATIVO"),
                         ([ID_PATRIMONIO] <> [ID_PATRIMONIO].[ID_PATRIMONIO])
              )
    )

[deltai]

Hy friend´s

Anybody to help me?

[deltai]

@AleksiAlkio, @Suvrutt_Gurjar, @Steve 

....may you help me about?

Tks