Looking at the Report Writer's Resource Report for the AA Report Dictionary, following are the available RW function in that Dictionary. I don't see any in-built function that says "originating". It may be necessary to custom write that function.
Id # 22005 Name: RW_GetDocNumbr
Id # 22006 Name: RW_aaBudgActGetCurr
Id # 22007 Name: RW_aaCalculatePercentage
Id # 22008 Name: RW_aaGetTotalAssignPercentage
Id # 22009 Name: RW_aaGetBoolYesNo
Id # 22010 Name: RW_aaGetCode
Id # 22011 Name: RW_aaGetCodeDesc
Id # 22012 Name: RW_aaGetCodeDescr
Id # 22013 Name: RW_aaGetCountAlphaCodes
Id # 22014 Name: RW_aaGetCountBoolCodes
Id # 22015 Name: RW_aaGetCountDateCodes
Id # 22016 Name: RW_aaGetCountNumCodes
Id # 22017 Name: RW_aaGetDocDesc
Id # 22018 Name: RW_aaGetErrorDesc
Id # 22019 Name: RW_aaGetMainTree
Id # 22020 Name: RW_aaGetNode
Id # 22021 Name: RW_aaGetTotalAssignCrAmt
Id # 22022 Name: RW_aaGetTotalAssignCrAmtGL
Id # 22023 Name: RW_aaGetTotalAssignCrAmtGLWork
Id # 22024 Name: RW_aaGetTotalAssignDrAmt
Id # 22025 Name: RW_aaGetTotalAssignDrAmtGL
Id # 22026 Name: RW_aaGetTotalAssignDrAmtGLWork
Id # 22027 Name: RW_aaGetTotalAssignPercentageGL
Id # 22028 Name: RW_aaGetTotalAssignPercentageGLWork
Id # 22029 Name: RW_aaGetTotalPercentageAsString
Id # 22030 Name: RW_aaGetTrxDimDescr
Id # 22031 Name: RW_aagGetPeriodString
Id # 22199 Name: RW_aaCalculatePercSubLedger
Id # 22200 Name: RW_aaCalculatePercentageNew
Id # 22201 Name: RW_aaGetErrorMsgforAliasImport
Id # 22202 Name: RW_aaGetTotalAssignCrAmtGLHist
Id # 22203 Name: RW_aaGetTotalAssignDrAmtGLHist
Id # 22204 Name: RW_aaGetTotalAssignPercentageGLHist
Id # 22207 Name: RW_aaCalculatePercentageGLWork
Id # 22217 Name: RW_aaUPRGetDispID_PostingEdits
Id # 22220 Name: RW_GetFADispDistID
Id # 22221 Name: RW_aaFA_GetAccountNumber
Id # 22222 Name: RW_aaFA_GetAcctDescription
Id # 22223 Name: RW_aaFA_GetAssetID
Id # 22224 Name: RW_aaFA_GetBookID
Id # 22225 Name: RW_aaFA_GetReportingLedger
Id # 22226 Name: RW_aaGetTrxDataType
Id # 22227 Name: RW_aaGetTrxDim
Id # 22232 Name: RW_aaGetDocDescr
Id # 22235 Name: RW_aaGetSeriesName
Id # 22245 Name: RW_GetAcctInfo
