There is a validation on the Target Sources page to ensure that the Datasource uses the same system type across targets. There needs to be a report to display those records, otherwise every project will have to create their own.
IE:
SELECT DSPCommon.dbo.ztSystemType.SystemType, derivedtbl_1.DataSourceName, COUNT(*) AS Expr1
FROM dbo.ttTargetSource INNER JOIN
(SELECT COUNT(DISTINCT ttTargetSource_1.SystemTypeID) AS SystemTypeCount, DataSource_1.DataSourceName, DataSource_1.DataSourceID
FROM dbo.ttTargetSource AS ttTargetSource_1 INNER JOIN
CranSoft.dbo.DataSource AS DataSource_1 ON ttTargetSource_1.SourceDataSource = DataSource_1.DataSourceID
GROUP BY DataSource_1.DataSourceName, DataSource_1.DataSourceID
HAVING (COUNT(DISTINCT ttTargetSource_1.SystemTypeID) > 1)) AS derivedtbl_1 ON
dbo.ttTargetSource.SourceDataSource = derivedtbl_1.DataSourceID INNER JOIN
DSPCommon.dbo.ztSystemType ON dbo.ttTargetSource.SystemTypeID = DSPCommon.dbo.ztSystemType.SystemTypeID
GROUP BY DSPCommon.dbo.ztSystemType.SystemType, derivedtbl_1.DataSourceName