it sounds like the determination for exclusion value is found in the sub report so you cannot actually exlude the values from your main report.
It is possible to suppress data in the main report based on a value form the sub report but there are a few things to remember when doing this.
1. YOu have to send the value from the sub-report back to the main report as a shared variable, it cannot just be a dispaly value in the sub-report
2. you cannot suoppress the subreport or it will not run. You can suppress all of the fields in a subreport and then suppress the section that it runs in when it is blank
3. suppression from a shared variable formula can only suppress data below where that value is garnered. meaning if you pull in the value from the subreport into GH1b, GH1a cannot be suppressed. Basically you have to consider making the shared vcariablinto GHa and then move all your other values below that so you can use the resulting variable as a condition.
4. you can only suppress rows so they are still all included in any sumamry withing the main report unless you explicitly exclude them via a running total or variable formula that does the calculations.