Update a Test Plan by the Excel Importing tool

Hi every one

Im starting with the .CFG configuration file of the excel import tool, I have the situation where 2 teams add TestCases to an actual TestPlan but for example the second time I import the same file with new testcases but it disassociates old ones. Is there any way to add them and conserves actuals?

Gracias

This is my CFG:
//Config for Testplan
testplan.dc:title=B1
testplan.XLSArtifactID="urn:com.ibm.rqm:testplan:98"
testplan.dc:description=B2
testplan.XLSLink=testcase

// use the data in the first row of a found script's column B
Start looking for scripts after row 2
testscript.XLSStartRow=8
testscript.XLSArtifactID=B
testscript.dc:title=B
testscript.dc:description=C
testscript.steps.type="execution"
testscript.steps.title=D
testscript.steps.name=D
testscript.steps.description=E
testscript.steps.expectedResult=F

// a new script starts when we encounter an empty row
testscript.XLSDelimeter=\n

// we want to use the data we got for each test script to create a test case
testcase.ID=testscript.XLSArtifactID
testcase.dc:title=testscript.dc:title
testcase.dc:description=testscript.dc:description
testcase.category term="Aplicación".value=B3
testcase.category term="Módulo".value=B4
testcase.category term="Área Responsable".value=B5
testcase.category term="Tipo de Prueba".value=B6