I need to build a baby gate for my dogs?

hi there,

I have a few mischievous dogs and I would like to have them out in the family room when we're in the family room (they like to run into other rooms and cause trouble, going through stuff, tearing up things and so on) so I'd like to made a "baby gate" so we can enjoy them in the family room with us without constantly wondering what trouble they are causing.

The opening to the room is approx 48 inches wide and I would like an easy (preferably somewhat asethcially pleasing) way to block off the room. It shouldn't have any holes like real baby gates do because two of my dogs can climb those like a ladder.

What material would we need to build something like this? Can I make something that's easy to put away when we are not using it?

What's the best options from people who are used to building things?

Thank you in advance!