Ya so, that's one way to do it.
Are the users that get these files interconnected? We have a lot of customer who do this sort of thing as well. Hospital x-rays..etc. We have great success with Cisco WAAS.
We've seen over 10 times improvement. It does this via..
-TCP optimization for specific applications. Not generalizations. i.e. It'll know SQL like traffic like x/y/z and will setup the streams that way. However, if it knows Oracle or SMTP is better another way - those sessions maintain those settings.
-Caching. So lets say a jpeg is sent from site a to site b and c. Well now when that jpeg is sent between c and b and a - it's cached and won't be retransmitted.
Lets say you change a paragraph in a .doc file with 2000 pictures in it that was emailed to you. Well, it was cached and WAAS can determine that only a paragraph was change and only transmit that portion.
Pretty slick product. Let me know if you want more information.
Curious, can you say what construction company? We do work for a few bigger named ones in the area - at least housing ones and a couple of...well, more Engineering/Architect firms beyond the home builders.