Crystal Reports Record Selection Formula Based on Two Date Fields

Hello Experts,

I am working on a report (Crystal Reports version 11), that uses a global date parameter to link multiple subreports.  When I run the report I enter a single date range and each subreport has the following in its record selection:
{MManpower.M_tTime} >= {?Pm-@Begin Range} and
{MManpower.M_tTime} <= {?Pm-@End Range}

My quandary is that I am trying to add a second date condition in the record selection using the following syntax:
(({MManpower.M_tTime} >= {?Pm-@Begin Range} and
{MManpower.M_tTime} <= {?Pm-@End Range})
or
({IIncident.I_tTimeTransmit} >= {?Pm-@Begin Range} and
{IIncident.I_tTimeTransmit} <= {?Pm-@End Range}))

But, I am not getting records back that are based on the second table.date field - I am only getting records back based on the first table.field.  Is this because the subreport link in the primary report is based on only the first table.field?  If so, is there a way to link the global date parameter in the subreport links to more than one table.field?  Or, is my syntax incorrect? Or do I need a different work-around?

Thank you for your help with this.
~Chopp