попробуйте использовать на внешнем в процедуре
например:
create or alter procedure GET_ALL_DATA
returns (
BASE integer,
ID integer,
NAME varchar(250))
as
begin
for execute statement 'select 1, id, name from dict_assortment'
into base, id, name do
suspend;
for execute statement 'select 2, id, name from dict_assortment'
on external 'C:\base2000\Db\db.fdb'
into base, id, name do
suspend;
end