How can I use one Thunderbolt connection for display and internet?

My new MBP (MacBook Pro 2014) has two Thunderbolt connections which are rapidly filling up. I use it on the desktop in 'closed clamshell' mode to drive two external monitors (in AC operation) with wired LAN connection. My monitors are now driven from a Thunderbolt connection and one HDMI connection in order to leave room for the wired ethernet via an adapter.

I am dissatisfied with the quality of text the HDMI displays @ 1920x1080p (the highest resolution supported by the monitor). Text edges do not display nearly as cleanly as on the other driven from a Thunderbolt/MiniDisplayPort connection to the same monitor (and it's mate) on the desktop. I'm wondering if there is some way to share the Ethernet and display functions to the other display as a workaround. The monitor (Dell U2413) has a looping MiniDisplayPort output. I am going to try looping the monitor output to the working ethernet adapter to see if it works.

Just asking what I should expect to confirm any other experiences you all may have had with this configuration. Any other advice or guidance on this would be appreciated.