Answer
No, as of Esri Maps for Salesforce 1.1, it is not possible to run a workflow on a subset or filter of an object as an alternative to running the workflow on the entire object.
However, a view or filter can be created when adding data from Salesforce or ArcGIS Online. This allows only the desired data to be recorded as a new layer.
Note:
Filtering objects when creating a layer allows for better control of the number of records added, hence increasing the performance when running a workflow.
For more information on setting filter criteria when adding data, refer to the following documentation, Esri Maps for Salesforce: Add data from Salesforce and Esri Maps for Salesforce: Add data from ArcGIS.