Checking custom property conditions and logging failures in synchronization

Hello,

I need to check property values on target system objects and generate any kind of report on the objects that fail the conditions.

Both or either a way to do this as a condition for an operation (e.g. deletion), and a way to do it without an actual change when passing the conditions would be very useful.

Anyone know if, for example, there is a way to produce custom errors into synchronization log from workflow or mapping conditions, or something?

Thanks!