Macros in MSP

Hi,

I have created a schedule by inserting subprojects. I do this activity every month and each time when I create the schedule I have to link the activity. but for the schedule with 3500 activities it becomes cumbersome. hence I want to create a macro to link these activities. The only problem is every time when the schedule is created, activity ID does not remains the same. I want to create the macro using the Unique ID present in MSP. Please help.

Thanks,