How to Separate Out lines and Create a GEDCOM to send to GEDMatch

I have both my biological and adoptive lines in one database. When I wish to work with either independently, I switch to the required parent couple. I need to create a GEDCOM of my biological lines only that I can upload to GEDMatch for genealogical matching purposes. What is the best way to create that GEDCOM in RM?
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You can drag and drop the biological line to a new database. Open your database and then open a new blank database. Just select the start person and select who to drag with them. For you I would start with a biological person above you. Then you can create the Gedcom from the new database. Hope this helps

if you create a group containing your biological lines you should be able to export a gedcom just for that group.