The answer is YES...you can put a T connector into your system and run off of an external tank. There are a couple different configuration such as before and after the regulator with pros and cons.
Here is an example of a system to hook up aux tanks
Stay Longer Propane Adapt Kit by Marshall Excelsior Com : RV Parts Nation
There are a few way to go that will give you options to use aux tanks, use your own tanks to fuel external devices like grills and/or both.
So, depending on your options and CG rules you could...
1. Have a local LP dealer come out and fuel you. (I just had that done at my CG today.)
2. You could adapt your rig to take external tanks.
If you do #2, you could ask the CG to allow the LP distributor to station a larger LP tank at your site to give you expanded capabilities. Otherwise, you might be looking at smaller tanks that you can haul to your rig and be small enough to store in a place near your MH that won't offend the CG management.
I'm certain there are a few variations on these options.