Yes. Have you thought about using the "DatabaseTimezone" translator property to define the source database location? See the override translator properties to define the timezone for each source, then time will be automatically converted to the server timezone. Check out the "Translator Overrides" tab on the vdb editor in the Teiid Designer to override the property.
If u are using "multi-source" feature, then there may not be tooling for this, but you can accomplish same thing by editing the vdb.xml file in the .vdb file.
Basically in your vdb.xml you extend the translator like
<translator description="" type="oracle" name="oracle-central"> <property value="GMT-6" name="DatabaseTimeZone"/> </translator>
and use "oracle-central" as translator name on your source.
Thank you Ramesh