Welcome to the Make community!
You can put a filter before the aggregator module, so that only the filtered items reach the aggregator. This is much easier than filtering the items afterwards.
To allow us to assist you with your scenario, please provide the following:
1. Relevant Screenshots
Please share screenshots of your scenario, any error messages, relevant module fields, and filters in question? It would really help other community members to see what you’re looking at.
2. Scenario Blueprint
Please export the scenario blueprint file to allow others to view the mapped variables in the module fields. At the bottom of the scenario editor, you can click on the three dots to find the Export Blueprint menu item.
3. Output Bundles of Modules
Please provide the output bundles of the modules by running the scenario (or get from the scenario History tab), then click the white speech bubble on the top-right of each module and select “Download input/output bundles”.
Providing the input/output bundles will allow others to replicate what is going on in the scenario even if they do not use the external service.
Following these steps will allow others to assist you here. Thanks!
— @samliew
P.S.: Did you know, the concepts of about 70% of questions asked on this forum are already covered in the Make Academy. Investing some effort into it will save you lots of time and frustration using Make later!