Is there any way to comment a block in HSPICE?
*Any line starting with * or $ is considered a comment. 

*HSPICE also treats things after "*" or "$" as comments.
The dollar sign ($) must be used for comments that do not begin in the first
character position on a line
 For example,

* RF=1K GAIN SHOULD BE 100
$ MAY THE FORCE BE WITH MY CIRCUIT
VIN 1 0 PL 0 0 5V 5NS $ 10v 50ns
R12 1 0 1MEG $ FEED BACK
.PARAM a=1w$comment a=1, w treated as a space and ignored
.PARAM a=1k$comment a=1e3, k is a scale factor


For multi-line comments there is no way but to add $ or * at start of each line.

An .END statement is the last statement in the input netlist file. Text that
follows the .END statement is a comment, and has no effect on the simulation thus the code which is needed to be ignored can also be placed there. 

for more details https://cseweb.ucsd.edu/classes/wi10/cse241a/assign/hspice_sa.pdf