Speech with an extra kid!

Our schedule with the SLP has been so erratic lately (she has been rescheduling) that we have had plenty of W's speech appointments after Iz gets out of preschool but its not official--with preschool out, she'll be there for all of them.  It is quite stressful for me :\  I have to try to keep her from interfering and occupied but ALL she wants to do is "help" W and be involved and take part.  W's SLP isn't very flexible and she seems to struggle having other kids around vying for her attention.  I'm trying to keep Iz separated but things will only get worse at the next session when the boys are out of school and all four of them are underfoot!