MacBook Pro 11,3 with dual Dell P2715Q 27" Monitors

I have two Dell P2715Q 27" external monitors I want to connect to my 15" MacBook Pro 11,3 with OSX 10.10.2 ordered around September 2014. I've tried connecting it as follows: note: tb = thunderbolt, dp = displayport, mdp = mini displayport First try --------- - tb 1 -> Dell P2715Q #1 dp in -> Dell P2715Q #1 dp out -> Dell P2715Q #2 mdp in In this case the two Dell screens will only mirror, and OS X does not seem to recognize that there are actually two displays attached. Second try ---------- - thunderbolt 1 -> Dell P2715Q #1 displayport in - thunderbolt 2 -> Dell P2715Q #2 displayport in In this case one screen will go on, but the other remains black and says there is no signal. side note --------- I also have an older 1920x1200 Dell display I want to use via HDMI for a total of 3 external displays, but I need to get an HDMI cable plus the first two screens working first.