Need to Modify Layers and Styes across series of DWGS

My partner and I are having a problem managing layers and styles across drawings. We are currently working on a project that has 15 drawings, and if we need to come up with a new layer or text/leader style, we are having to go into each drawing individually and change the style and add a layer one by one, and it is becoming time consuming and can be quite a burden. Is there any way that we can link the drawings so that a style or layer change can be made across all drawings at one time, or are we stuck doing it like we are. These are 15 individual drawings and not one drawing with 15 sheets. Thanks in advance.

I have an application in VB6 that iterates through several dwg files changing attributes on blocks... perhaps I can change it in order to make what you need. Attach a dwg file with your layers and styles, and other dwg without those, and letme a few days