Simulation package under Delphi wanted

I am looking for a package which supports discrete simulation of
processes. I am currently using an (slef written) extension to Pascal
which supports the basis Simula-like process interactions:
Activate, Reactivate, Hold, Passivate, Cancel.
The processes are modelled as individual procedures from which many
instances may occur. In contrast to conventional handling, a procedure
may be left for work on another procedure (process). The Pascal
package heaviliy relies on low level stack handling and swapping,
This concept is also called multithreading, but the other then
'normal' the mechanism to jump to other processes is completely in the
hands of the simulation (i.e. an event mechanism).

I would like to see a mechanism to swap tasks (in Delphi 32 bit
version) or a more complete simulation package in Delphi.

Any suggestions are welcome, preferably also via email.

Ruud Th. van der Ham