The dataset is relatively small so I don't need a dictionary. Basically just looking for the python version of this VBScript that I found:
Function FindLabel ( [RelateFieldofLayer] )
Set gp = CreateObject("esriGeoprocessing.GPDispatch.1")
strWhereClause = chr(34) & "RelateFieldofTable" & chr(34) & " = '" & [RelateFieldofLayer] & "'"
strpTable = "PathToRelatedTable"
Set prows = gp.searchcursor(strpTable,strWhereClause)
Set prow = prows.next
Do until prow is nothing
strLabel = prow.LabelField
FindLabel = FindLabel & strLabel & vbnewline
Set prow = prows.next
Loop
End Function