Hi @leahc and welcome to the forum!
If your pipetting device for this step (sounds like a resuspension) is either the 1mL channels or MPH96, then your best bet would be to use the PipettingTools library of the STAR Tool Suite.
Simply import the pkg, and all libraries of the suite, including PipettingTools will be copied into your VENUS installation. This library is supported on STAR and VANTAGE platforms.
There are functions which allows for custom aspiration and dispense step behavior where the height of the ends of the tips can be specified to your needs:
You will still use labware shifts between target points within the well, but this will give you the control you are seeking.
For MPH96, you can perform mixing by looping consecutive aspiration and dispense steps at each mix point. You just need to specify parameters for liquid following, liquid class, start and end heights, retract distance etc.
Hope this helps!
-Nick