BSP Dungeon generation with loops

I've made algorithm based on it:

http://ift.tt/1DSoAE8

but it does not provide loops between rooms.

Red lines are connections between rooms made by original BSP dungeon algorithm Yellow lines are the connections I wish to be also generated and randomly.

Are there any resources for such a thing? (couldn't find)

here goes my BSPTree class, maybe someone find it usefull to come up with an idea:

http://ift.tt/2dGBqjS

and here is how I use this class to generate level template:

http://ift.tt/2dodTsM