Unless you have a good reason not to, the first thing I would do is put all personnel into one database, and add a field for department. This is pretty straight forward "read the manual" stuff, however heres an exmaple
<? if ($employee_id <> "") {
$qry = mysql_select("select * from table where employee_id = $employee_id");
$row = mysql_query_array($qry);
echo $row["lastname"] ." - ". $row["firstname"];
etc...
} else {
$qry = mysql_select("select * from table");
while($row = mysql_query_array($qry)) {
echo "<a href='employee.php?employee_id=".$row["employee_id"]."'>";
echo $row["lastname"];
echo "</a></br>/n"
}
}