You can do this, currently, IF the adventures are offered as ADD-ONS (a product type) in the Roll20 Marketplace. Majority / most adventures ARE offered in Add-On format, so you can do that. The ones that aren't offered as Add-Ons, and are only offered as Modules (a product type in the Roll20 Marketplace) such-as for example ICEWIND DALE REMASTERED, it's usually because they are considered too big to combine with others, in terms of the number of assets (Handouts, Pages, Decks, Tokens) such that adding more could become too-many and cause a slowdown or lag or other bugs in the game. Since you have PRO account, you have Transmogrify feature access, and this is the best way to Move your contents back-and-forth between different game tables. Think about this for a while, and decide how you can use it best for your purposes. One idea is to create a Library (Holding tank) game table and install as much as possible, or everything if you can, but don't necessarily run your game day-to-day from that table. Run your game in a cleaner table (game) with fewer modules installed, but with the Characters. Go to your Library game in between sessions to read, choose, and pull over using Transmogrify. This method will help prevent your main game table from experiencing the possible Lag, but gives you a GM-Working table to look through all your resources. Another transmog method that is a different approach, install each Module on its own Game, and use Transmogrify to move the Characters cleanly and quickly to whatever Module they (or you) want to do next. This is the same method as Character Vault (now called Roll20 Characters) but faster and easier because you are PRO account. If your players are playing through any Mega-huge modules like Icewind Dale then you might try this method. It's a fine suggestion to say allow 1 game table to fit literally everything, but there might be WWW (web) limitations that makes that unadvisable and that's why they set it up like it is, but fortunately there are some work-arounds. I really think the short-and-quick answer you're looking for is: Buy the Add-On version of the adventures you want, because you can install as many Add-Ons as you want, on one single game.
