That will partially subdivide the same area more than once? Like this plugin > http://www.zbrushcentral.com/showthread.php?t=28045&page=1&pp=15 But this one isn’t compatible with zbrush 3.5
There’s no version of this for 3.5 R3. It may be possible to update; I’ll take a look when I have time after the ZBrush 4 launch dust has settled.
In the meantime you can partially subdivide a mesh by masking or hiding part of the mesh at the lowest subdivision level, then subdividing. If you paint a mask you will probably want to invert the mask before subdividing.
Triangles can be messy. It hinders alor of work