How to use index in EL expression?

 Hi, it is also convenient to use the iteration of ELs such as
<c:if test="${!empty param.t${i}vorname}">.
Of course, it doesn't work. But, I'd like to do the following iteration.

<c:forEach var="i" begin="1" end="8">
<sql:update var="insert${i}">
insert into member values (1,?::integer,${i},?,?,?)
  <sql:param value='${param.department}' />
  <sql:param value='${teamid}' />
  <sql:param value="${param.t${i}vorname}" />
  <sql:param value="${param.t${i}name}" />
</sql:update>
</c:forEach>

 Is there some idea for this without whole description expanding i?

Regards,