i need an element with the characteristics

<!ELEMENT section ((comment*)|definition|(comment*))>

but that is ambiguous, i get the next message in visual studio

Multiple definition of element 'comment' causes the content model to become ambiguous. A content model must be formed such that during validation of an element information item sequence, the particle contained directly, indirectly or implicitly therein with which to attempt to validate each item in the sequence in turn can be uniquely determined without examining the content or attributes of that item, and without any information about the items in the remainder of the sequence.

So how can i write correctly that? the correct structure is one definition surrounded by possibles comments elements.