You have to suppress both and in theory group 1 footer if all the customers in that division are in your suppression group.
However, I think you are trying to suppress all parts of a group from header to footer for all of group2 and group 3 so why not just exclude those groups using a group select criteria on group 2?
For group 1 suppression you will need to suppress all parts based on checking the count of customers not in your suppression criteria.
Create a formula field
if Not({SO_PickingSheetWrk.CustomerNo}like "HDCOM") then 1 else 0
sum this at group level 1
suppression is then sum(formula,group1)=0

so I have something similar to this. I have a report that has a repeating header. But now I want to add a sub-report in one of the footers and I do not want the main report header to repeat onto the sub-report. how do I stop that?

But the report header is on the main report. I want it to show for everything that is on the main report for all pages, but I do not want it to show up on the page of my sub report which is in a report footer section on the main report.

How do I say if footer contains sub report do not include the report header from the main report onto the pages that the sub report prints on.

so the main report is an invoice per say - and the sub report is just instructions with its own different header.

Now it is printing both headers when it prints the sub report. I thought even if I take the data out of the sub report and just put it directly into the the footer section - is there a way to stop the header from printing only on that footer