Hi Rob 

Thanks for posting in the Community! To combine individual swim lanes into a pool use the Group feature. Select both swim lanes right click and select "Group" to combine them into one shape! 

I hope this helps! Let us know if you have any additional questions. 

In my opinion his is being over engineered. I ran into this when I first started with Lucid. If you grab a swimlane from left hand side you can click on the object and manually add or remove swimlanes without having to group separate swimlanes together. This also is convenient if you end up add or removing swimlanes down the road.

Hi Vince this is a great tip - thanks for your adding your thoughts!