I recommend that you make a folder for Shopper, WxW, Regular or any other maps in the \Steam\steamapps\common\worms reloaded\UserLandscapes\

Than you install in this specific folder the map pack for this game style. Whenever your friends want play Shopper or Regular or any other game style, than you could delete the current maps in the "\UserLandscapes" folder and copy the desired maps to the "\UserLandscapes" folder. You have this way not so much maps in the "\UserLandscape" folder.

Copy the desired maps to the "\UserLandscapes" folder before you start the game.