Hi ViviB,
You can create a manual check batch entry and select both invoices for payment for that vendor. Or create a System Check run (Print/Post Checks and Advices) to generate a check for the vendor that would select these and other invoices.
There are training videos available on our website, accessible from the Resources menu and the Video Gallery area, to see how certain functions like this can be done for either
System Check Processing or
Manual Check Batches.