Automatically aligning multiple rectangles

I am a CC member and using the latest Illustrator. I am using Illustrator to create multiple templates for automatic mat cutting of A1 matts. It is critical that the sections between images be even and consistent. The matts will all have a 3cm outside mat edge with multiple rectagles in the interior. The outside is difined by locked guides. Is there a way to automatically align rectangles, both horizontally and vertically in the interior of the mat. doing the measurements by hand is time consuming and not perfectly accurate.

I look forward to you answers,

Jim