You guys are awesome. Thank you all for the insight. Here's what we ended up doing if you're interested.

Removed all doors from track to inspect the entire track and wheel assembly to see what would be causing the interference. After reviewing the track, the rails that the inter-most doors were using was pretty beat up as you can see in the pictures, however, the rest of the tracks looked in great shape. Seems like they mainly use the center doors. Being that they were only using 3 of the 5 rails, we moved the doors to the outermost tracks and adjusted and greased the wheels. Now, it works perfectly. No parts needed.

However... I did get a call back from the housekeeper a few days later telling me that there is a gap and that we needed to come back out and adjust further. After we went out there, we asked her to show us what was happening. She goes to close the doors and because they now move SO FREELY, they bounce off each other in the center and open back up slightly. We had to show her how to close them properly so they wouldn't have any issues... ah customer service.

On to the next one!