Entitlement.TemplateiOS.xml update

Hello, i have this in Entitlement.TemplateiOS.xml file :

<%getTaskAllowKey%>

<%applicationIdentifier%>

<%pushNotificationKey%>

<%keychainAccessGroups%>

And <%keychainAccessGroups%> is finally replaced with :

keychain-access-groups

APPPREFIX.APPNAME

What I need is to add one more record there. So in generated file would be :

keychain-access-groups

APPPREFIX.APPNAME

APPPREFIX.mycustomstring

How can I do that? I know i can do it manually in release folder but i need to generate appprefix because of different prefixes on different machines ...