Approach - 1:
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1. Use Process Deatils per Process Model report and get the process ids using a!queryProcessAnalytics/ getportalreportdatasubset with following as filters or context:
	-	processModelId IN (id of process model 'A')
		AND
	- 	Status IN (Active, Paused etc)

2. Get all subprocess ids by using 'Get All Synchronous sub-process ids' plugin (It would be worth checking if there are any other plugins of this kind and the results are as per your expectations) for each process id found in Step - 1.

3. Use 'All processes' (add process model id [so that it can be used as filter] and make a save as) report and get the process ids using a!queryProcessAnalytics/ getportalreportdatasubset with following as filters:
	-	processId IN (dataset obtained in Step - 2)
		AND
	-	processModelNames IN (B and C)
		AND
	- 	Status IN (Active, Paused etc)
4. Amalgamate the ids obtained in Step - 1 and Step - 3. This is your final array of process id on which you need to perform updates.


Approach - 2: 
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1. Make use of a!queryProcessAnalytics/ getportalreportdatasubset and get all the process ids with following as filters or context:
	-	processModelId IN (id of process model 'A',id of process model 'B',id of process model 'C')
		AND
	- 	Status IN (Active, Paused etc)
2. Process ids obtained in Step - 1 is your final array of process id on which you need to perform updates.

Note: 
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1. Please make sure that queryProcessAnalytics/ getportalreportdatasubset fails if they try to return data more than the limited rows offered by the execution engine(This depends on the resources.appian.analytics.application.maxreportrows= setting.)
2. If you are on 7.8, please make use of a!queryProcessAnalytics else use getportalreportdatasubset (Portal to SAIL plugin)