$ cat ./Test.java 
package test.test;

import java.some.common.collect1.Lists1;

import static java.some.common.collect1.Lists1.asList;

import com.google.common.collect.Lists;

import static com.google.common.collect.Lists.asList;

public class Test {
    public void test() {
        Lists.cartesianProduct(null, null);
        asList(null, null);
    }
}

$ cat ./config.xml 
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
          "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<module name="Checker">
    <module name="TreeWalker">
    <module name="ImportOrder">
      <property name="groups" value="/^java\./,javax,org,com,net,edu,io"/>
      <property name="ordered" value="true"/>
      <property name="separated" value="true"/>
      <property name="option" value="under"/>
      <property name="useContainerOrderingForStatic" value="true"/>
    </module>

    </module>
</module>

Starting audit...
[ERROR] /var/tmp/Test.java:5: Extra separation in import group before
 'java.some.common.collect1.Lists1.asList' [ImportOrder]
[ERROR] /var/tmp/Test.java:9: Extra separation in import group before
 'com.google.common.collect.Lists.asList' [ImportOrder]
Audit done.
Checkstyle ends with 2 errors.

$ cat ./style.importorder 
9=\#net
8=net
7=\#com
6=com
5=\#org
13=\#io
4=org
12=io
3=\#javax
11=\#edu
2=javax
10=edu
1=\#java
0=java