If you are SAP BusinessObjects BI Platform Administrator and looking to find Users who are part of multiple groups, this blog is for your reference.

Query to get the groups a user is belonging to:

SELECT SI_ID, SI_NAME, SI_USERGROUPS FROM CI_SYSTEMOBJECTS WHERE SI_KIND='User' AND SI_ID = <id>

Here is the JAVA SDK sample to print the list of groups, each User is belonging to:

package com.sap.businessobjects.bi.samples;

import java.util.Iterator;
import java.util.Set;

import com.businessobjects.bcm.BCM;
import com.crystaldecisions.sdk.exception.SDKException;
import com.crystaldecisions.sdk.framework.CrystalEnterprise;
import com.crystaldecisions.sdk.framework.IEnterpriseSession;
import com.crystaldecisions.sdk.framework.ISessionMgr;
import com.crystaldecisions.sdk.occa.infostore.IInfoObject;
import com.crystaldecisions.sdk.occa.infostore.IInfoObjects;
import com.crystaldecisions.sdk.occa.infostore.IInfoStore;
import com.crystaldecisions.sdk.plugin.desktop.user.IUser;

public class listOfUsersInMoreThanOneGroup 
{
	public static void main (String[] agrs) 
	{
		Set<Integer> setUserGroups;
		String cmsname = null;
		String username = null;
		String password = null;
		int x = 0;
		int y = 1;
		Object groupID = null;
		cmsname = "localhost:6400";
		username = "administrator"; 
		password = "Password1";
		IEnterpriseSession boSession = null;
		ISessionMgr lSessionMgr = null;
		IInfoStore infoStore = null;
		IInfoObjects users = null;
		IInfoObjects boUserGroups = null;
		IInfoObject boUserGroup = null;
		IUser user = null;

		try 
		{
			BCM.initializeSAPJCE();
			lSessionMgr = CrystalEnterprise.getSessionMgr();	
			System.out.println("LIST OF USERS IN MORE THAN ONE GROUP: ");
			System.out.println();
			boSession = lSessionMgr.logon(username, password, cmsname, "secEnterprise");
			infoStore = (IInfoStore)boSession.getService("", "InfoStore");
			for(int i=0;i<1;i++)
			{
				users = infoStore.query("SELECT si_id, SI_USERGROUPS FROM CI_SYSTEMOBJECTS WHERE SI_KIND='User'");
				if(users.size() == 0)
				{ 
					break; 
				}
				for(Iterator<?> iuser = users.iterator() ; iuser.hasNext() ; )
				{
					user = (IUser) iuser.next();
					setUserGroups = user.getGroups();	
					if (setUserGroups.size() > 1)
					{
						x=1;
						System.out.println("  "+y+" - User '" + user.getTitle() + "' is part of " + setUserGroups.size() + " groups, and they are: ");
						for(Iterator<?> iGroup = setUserGroups.iterator() ; iGroup.hasNext() ; )
						{
							groupID = iGroup.next();
							boUserGroups = infoStore.query("SELECT SI_NAME FROM CI_SYSTEMOBJECTS WHERE SI_KIND = 'UserGroup' AND SI_ID = '" + groupID + "'");
							boUserGroup = (IInfoObject) boUserGroups.get(0);
							System.out.println("       "+ x + " - " + boUserGroup.getTitle());
							x++;
						}
						System.out.println();
						y++;
					}
				}
			}
		}
		catch (SDKException e) 
		{
			e.printStackTrace();
		} 
		finally 
		{
			if (boSession!= null) 
			{
				boSession.logoff();
			}
		}
	}
}

Regards, Venkat.