stacktrace from running 2 rivers ...

gistfile1.txt

[2014-08-04 13:01:45,041][ERROR][de.saly.elasticsearch.river.imap.IMAPRiver] Unable to start IMAPRiver due to org.quartz.ObjectAlreadyExistsException: Unable to store Trigger with name: 'intervaltrigger' and group: 'group1', because one already exists with this identification.
org.quartz.ObjectAlreadyExistsException: Unable to store Trigger with name: 'intervaltrigger' and group: 'group1', because one already exists with this identification.
	at org.quartz.simpl.RAMJobStore.storeTrigger(RAMJobStore.java:415)
	at org.quartz.simpl.RAMJobStore.storeJobAndTrigger(RAMJobStore.java:252)
	at org.quartz.core.QuartzScheduler.scheduleJob(QuartzScheduler.java:886)
	at org.quartz.impl.StdScheduler.scheduleJob(StdScheduler.java:249)
	at de.saly.elasticsearch.river.imap.IMAPRiver.start(IMAPRiver.java:283)
	at org.elasticsearch.river.RiversService.createRiver(RiversService.java:148)
	at org.elasticsearch.river.RiversService$ApplyRivers$2.onResponse(RiversService.java:275)
	at org.elasticsearch.river.RiversService$ApplyRivers$2.onResponse(RiversService.java:269)
	at org.elasticsearch.action.support.TransportAction$ThreadedActionListener$1.run(TransportAction.java:95)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:744)

I am having this problem running two imap rivers.
My intention was to have two rivers feeding two indexes for two imap accounts on the same IMAP server. When I try to add the second river, I get the error above.
It appears to be the trigger name and group name cause the problem. Would it be possible to create the trigger and group name based on the index or river name?