Well, you can add a sweep around the analyses which is varying the actimes - as follows:
Code:

//
parameters act=0.5u
V1 (in 0) vsource type=sine mag=1 freq=1M ampl=1.2
R1 (in out) resistor r=1k
C1 (out 0) capacitor c=1p

sweepact sweep param=act start=0.1u stop=0.8u step=0.1u {
    ac ac start=1 stop=1G
    tran tran stop=1u acnames=[ac] actimes=[act]
} 

Of course this is a completely silly example...

I suspect this is not what you're asking (it wasn't very precise). Are you asking to do a single transient where the actimes is a sweep rather than a list of literal values? If so, you can't do that... you should contact http://support.cadence.com as it's a reasonable request for an enhancement.

Andrew.

Hi Aaron,
I recently asked the support for that. The answer I got:
"as for tran and actimes there is yet no such advanced “acperiod” option, you could also do a for loop and run a tran for each code."
- B O E