Well, I have purchased a Silver membership as recommended.
Once my head stops spinning from all of the options available to me I will dive in but I do have one more quick question:
I already find the "custom fields" add on handles links to external tables:
<field name="YOURFIELDNAME" type="jevcfdblist" default="-1" label="Select Sensor Value" required="0" description="Select List tool tip" allowoverride="1"
tablename="joomla0402.calefjgs" valuefield="sensor" labelfield="Sensor Value"
filter="1" multifilter="0" access="1" requiredmessage="The sensor value is required" readaccess="1"/>
is it capable of handling a concatenated list of database values? e.g.,
valuefield="id" labelfield="last_name first_name middle_initial"