```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>(t) Medications-Medications@14:52:51</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <subquery_constraint>
        <first_query>
            <query_id>Event 1</query_id>
            <join_column>STARTDATE</join_column>
            <aggregate_operator>FIRST</aggregate_operator>
        </first_query>
        <operator>LESS</operator>
        <second_query>
            <query_id>Event 2</query_id>
            <join_column>STARTDATE</join_column>
            <aggregate_operator>FIRST</aggregate_operator>
        </second_query>
    </subquery_constraint>
    <subquery>
        <query_id>Event 1</query_id>
        <query_type>EVENT</query_type>
        <query_name>Event 1</query_name>
        <query_timing>SAMEINSTANCENUM</query_timing>
        <specificity_scale>0</specificity_scale>
        <panel>
            <panel_number>1</panel_number>
            <panel_timing>SAMEINSTANCENUM</panel_timing>
            <panel_accuracy_scale>100</panel_accuracy_scale>
            <invert>0</invert>
            <total_item_occurrences>1</total_item_occurrences>
            <item>
                <hlevel>1</hlevel>
                <item_name>Medications</item_name>
                <item_key>\\i2b2_MEDS\i2b2\Medications\</item_key>
                <item_icon>FA</item_icon>
                <tooltip>Medications</tooltip>
                <class>ENC</class>
                <constrain_by_modifier>
                    <modifier_name>Patient Instructions</modifier_name>
                    <modifier_key>\\i2b2_MEDS\Medication\Instructions\</modifier_key>
                    <applied_path>\i2b2\Medications\%</applied_path>
                </constrain_by_modifier>
                <item_is_synonym>false</item_is_synonym>
            </item>
        </panel>
    </subquery>
    <subquery>
        <query_id>Event 2</query_id>
        <query_type>EVENT</query_type>
        <query_name>Event 2</query_name>
        <query_timing>SAMEINSTANCENUM</query_timing>
        <specificity_scale>0</specificity_scale>
        <panel>
            <panel_number>1</panel_number>
            <panel_timing>SAMEINSTANCENUM</panel_timing>
            <panel_accuracy_scale>100</panel_accuracy_scale>
            <invert>0</invert>
            <total_item_occurrences>1</total_item_occurrences>
            <item>
                <hlevel>1</hlevel>
                <item_name>Medications</item_name>
                <item_key>\\i2b2_MEDS\i2b2\Medications\</item_key>
                <item_icon>FA</item_icon>
                <tooltip>Medications</tooltip>
                <class>ENC</class>
                <constrain_by_modifier>
                    <modifier_name>Route</modifier_name>
                    <modifier_key>\\i2b2_MEDS\Medication\Route\</modifier_key>
                    <applied_path>\i2b2\Medications\%</applied_path>
                </constrain_by_modifier>
                <item_is_synonym>false</item_is_synonym>
            </item>
        </panel>
    </subquery>
</ns4:query_definition>

```

I want to find all medication events where the start date of the first medication event is less than the start date of the second medication event, considering the same instance number and with specificity scale set to 0. The first subquery will search for medication events with no constraints by modifier and the second subquery will search for medication events constrained by the route modifier.