I do not think it is possible to automatically assign creases to multiple sets of geometry using zscript. However Pixologic could possibly create a plugin that would accomplish that.
Although not completely automatic you could export group tags in the .obj file. This would make it easy to select the groups in ZBrush (polygroups) and add creases. Maya and Modo selection sets are exported as .obj groups which are imported into ZBrush as polygroups. Can 3DSmax export groups according to materials or selections ?
If you know your way around 3DSmax modules perhaps you could add ‘g’ tags for the smoothing group polygons and for regular polygons.
For example, in the following .obj polygon definition list the ‘g’ tells the .obj importer that the following polygons belong to group default. You can add ‘g’ tags anywhere you want in the polygon definition list, it does not have to be next to a ‘usemtl’ tag.
usemtl left
g Default
f 3/7 15/26 9/16 13/22
f 4/8 17/28 9/16 15/26
f 7/14 23/46 12/21 22/43
f 3/7 13/23 12/21 23/46
f 7/14 24/47 14/25 23/46
f 8/15 25/48 14/25 24/47
f 4/8 15/26 14/25 25/48
f 3/7 23/46 14/25 15/26
f 8/15 26/49 16/27 25/48
f 4/8 25/48 16/27 17/29
f 8/15 24/47 18/31 26/50
f 7/14 22/44 18/31 24/47
usemtl right
f 1/1 11/18 9/16 17/28
f 2/4 13/22 9/16 11/18
f 5/9 19/32 10/17 21/39
f 6/12 20/35 10/17 19/32
f 2/5 11/19 10/17 20/36
f 1/2 21/40 10/17 11/20
f 6/12 22/43 12/21 20/37
f 2/6 20/38 12/21 13/24
f 5/10 21/41 16/27 26/51
f 1/3 17/30 16/27 21/42
f 5/11 26/52 18/31 19/33
f 6/13 19/34 18/31 22/45
polygons: 24