Importing both an iPhoto and an Aperture library into Photos

I am a digital scrapbooker so I have an Aperture library for my photos and an iPhoto library for my digital supplies/graphics.

I have successful imported the iPhoto library into Photos and now would like to import my Aperture library too and have them as one library in Photos (I will create separate folders for them later in Photos).

Do I just choose the Aperture photo library to import into Photos (holding the option key on open)? Will that bring everything from Aperture into Photos with the iPhoto stuff that's already in there or start a separate library in Photos? I would like to have everything as one library now.

Thanks in advance for any advice.