I'm not sure what the previous response was trying to say, but in the spectre netlist you can do:
subckt block (d e)
I1 (d f) myinv
I2 (e g) myinv
ic f=3 g=0
However, ADE doesn't provide any way to do this - unless you created your own component to netlist an ic statement from an instance in the design, maybe.
You can however do this:
at the top level (so assuming that you have all your instances called BLOCK something, and the node inside called f, it will do an initial condition on all matching instances. ADE doesn't really have a way to define this through a form, but all you have to do is put the line in a file called "myIC.scs" (say; make sure it has a .scs suffix) and then reference this via Setup->Model Libraries or the Definition Files line on Setup->Simulation Files.