getUsersInMembership()

Hi.

Can I get the list of all the users in a Membership with Bonita 6.3.1 ?
I search in the IdentityApi but there is only getUsersInRole() and getUsersInGroup().
I need something like getUsersInMembership(roleId, groupId), or getUsersInMembership(membershipId) + getMembership(roleId, groupId) or getUsersInRoleAndGroup(roleId, groupId).

If you know where I can find something like this, it will help me a lot.

Thanks in advance.

PS : I can combine getUsersInRole() and getUsersInGroup() like this :

List list1 = getUsersInRole();
List list2 = getUsersInGroup();
List list3 = new ArrayList();
for (User u: list1) {
if (list2.contains(u)) list3.add(u);
}

But I don’t want to create a function if it already exists.