Cognos Schedule Issue

[davidcognos]

There are 2 datasources when we run a cognos report for selection. But only one is to be used which has the required table in that database.when we schedule a cognos job, cognos is picking the first datasource which doesn't have the required table in it. The datasource names are similar with convention and a suffix being attached to second datasource. I have explicilty given the datasource selection in the schedule prompt for values option also. But still when the schedule runs, the picks the first datasource and throws the error that table is not present in the database.  How can we make sure that right datasource is automatically selected during the schedule??