How do I stretch a gallery but contain the stretch to the layouter grid using Editor X?

I'm creating a website for a estate agency and so for each property listing I have created a 2 x 1 grid where I have a wix pro gallery of the property photos on the left side of the grid and a description of the property on the right side of the grid. I want the gallery to stretch but just to the dimensions of the left side of the grid just like you would do with a single image. However, when I select stretch, the gallery stretches to the size of entire section, covering my description also. Any help would be greatly appreciated. Thank you. Matt.