Get IDM id1 from a different Entity Type

Hi, I need to get the value for id1 variable for a different Entity type of a context. Example: For the contract schedule I have this context below and I need the id1 of the InforItemMaster.

How should I create the XQuery for this?

{
"type": "inforBusinessContext",
"data": {
"screenId": "ln_tdpur3101m300",
"logicalId": "lid://infor.ln.ln_test_100",
"entities": [
{
"visible": false,
"readonly": true,
"entityType": "company",
"id1": 100
},
{
"accountingEntity": "infor.ln.100",
"visible": true,
"readonly": false,
"entityType": "InforContractSchedule",
"id2": 10,
"id1": 500000004,
"id4": 0,
"id3": "",
"drillbackURL": "?LogicalId=lid://infor.ln.ln_test_100&ICMDrillback=true&Session=tdpur3601m000&SessionIndex=1&Filter=NTAwMDAwMDA0Xyx8LF8xMF8sfCxfXyx8LF8w&Enc=1&Mode=64",
"lnTable": "tdpur301"
},
{
"accountingEntity": "infor.ln.100",
"visible": true,
"readonly": true,
"entityType": "InforItemMaster",
"id1": " 0390534000",
"name": "Kodiersystem Vatereinsatz komp",
"drillbackURL": "?LogicalId=lid://infor.ln.ln_test_100&ICMDrillback=true&Session=tcibd0501m000&SessionIndex=1&Filter=ICAgICAgICAgMDM5MDUzNDAwMA==&Enc=1&Mode=64",
"bodReference": {
"accountingEntity": 100,
"noun": "ItemMaster",
"documentId": "0390534000"
},
"lnTable": "tcibd001"
}

Thanks
Alex