Run a query on linked tables to create a new datasource

Question

Using Crystal XI
I have a report that draws from two data sources.  They can't be joined at the server side, but they are linked in Crystal Database Expert. 
I can't figure out if Crystal gives me a way to write an SQL Query to run an aggregate function referencing both tables.  The results of this query would be the datasource for a graph in the report.  I'm wondering if Crystal gives me a way, maybe through subreports, to write the query I need.
More concretely:
And I want to include in my datasource alarmId, Hour and the Maximum amount of calls received in any one hour for any one station (this maximum is to provide scale for a graph)
In one table nameed AlarmStartTimes I have data like
Alarms
AlarmID  Hour    Recipient
Alarm1       8       Joe
Alarm23  10      Mark
Alarm60  7      Joe
Alarm95  8      Linda
In another I have data like
EELocation
Recipient   Location
Joe         Station1
Mark         Station2
Linda          Station1
So if I could just join my talbes at the server side I'd use a query like:
select *, max(select count(AlarmID) from Alarms, EELocation from Alarms Join EELocationo on Alarms.Recipient=EELocation.Recipient group by Hour, Location) AS  from Alarms
Anyway, that's probably got a syntax error or 4 in it, but you get the idea.
I can't group on the database side.  Since Crystal is able to link the two tables and successfully group them out by Location, it seems like there should be some way for me to run a query against the tables reflecting that existing link, but I can't see how to do it.
The reason I can't link on database side is that the data is in two databases, and it's not known what the location of the databases is at report-writing time.  The location of the databases gets set via the Crystal API when the report is launched from an application.

Answer 1

Since you have 2 datasource in the report you are limited on what you can use in crystal, such as crystal will not allow you to use sql expressions.