How to show specified data in a RG?

Hi everyone, I would like to show certain orders in a Repeating Group (RG). Each order has to be made in a specified machine. The field machine is a text field and contains the values:M1,M2,M3 … until M8. This field tells me in which machine the order will be made.

I would like that the RG only shows all the orders that are assigned to more than one machine, for instance, M3, M4, M7 and M8. What I manage to do is that the RG shows me all the orders of one machine (see example below), but I canno’t seem to find the way to tell bubble something like: maquina = M3 or M4 or M7 or M8. So, more than just one machine.


Thanks in advanced for your help!!!