Getting all available access groups in RTC programmatically

I am trying to get all the existing access groups from RTC using java API but only the first 250 results are always returned.I have tried using both getAccessGroups and IAccessGroupClientService but both are returning the same 250 results.Is there any other way to get all the available access groups at once? Also a filter which enables me to get the access group UUID using access group name is also welcome.Many thanks in advance!