looking for broker with this function..

is there any broker can do this :

i trade in account A(1000$), and there are account B、C、D...flowing the same trade acting and margin management of the account A ..

since i just trade in account A,and dont know the others, so i trade the only 1000$, but not the total sum of all the accounts..

looking for this because i found myself can trade well with 1000$ ervery time ,but can not keep excellent if the money amount change to 10,000$ or more..