Assuming you are using the ModBus to VFD for spindle control and you have a VFD that allows it, you can use Intelligent Input Modes to set up a path to get a spindle pause when needed.
On a Hitachi VFD, these are called Intelligent Input Terminals. You configure the VFD in a way that the pause is initiated with a switch. Mine is currently set up this way using “Force Terminal Mode”.
I don’t think the HY VFDs have this capability but I personally have no experience with them.