SAP PI Mapping collect

Hi.

I need some help to complete my requirment in a graphical mapping for PI 7.31.

The problem is that we receive a XMl file and we have to generate some IDOCS.

I have this structure of the XML file .

<segment header> 1 to N

<Segment item> 0 to N in segment header, with field <field1> mandatory in this segment

</segment header>

I have to generate so many IDOCS as different item fied <field1> value come by header.

For example if we have this:

<header>

<item>

<field1> ZTT

</item>

<item>

<field1> ZTT

</item>

<item>

<field1> ZRR

</item>

</header>

<header>

<item>

<field1> ZGG

</item>

<item>

<field1> ZGG

</item>

</header>

I should generate 3 IDOCS, 1 for ZTT , other for ZRR and other one for ZGG.

If the example is this:

<header>

No item is 0 to N cardinality

</header>

<header>

<item>

<field1> ZTT

</item>

<item>

<field1> ZTT

</item>

</header>

<header>

<item>

<field1> ZTT

</item>

<item>

<field1> ZTT

</item>

</header>

I should generate 2 IDOCs 1 for the ZTT of the second <header> and 1 more for the third <header>

So I should collect by field1 but depending of the lvel of the header...

Could you help me with a graphical mapping?

Thanks.