Yes you can.
In the Advance manager select the table editor icon. Then, in the astorRules table select the line that reads "JointsGuiAllowedSections". You can use filter to help find it.
In that table, you will see on line 31 that in manages join control "Grabrail". It tells us that the allowed section is O.
After you will go under Astor Profiles and select the "ProfileMasterTable", again, you can use filter option to find it. You then find the category you want to add. In you case I beleive it would be the AISC_HSS_Square. If you scroll to the left, under the column "SubTypName" you will see that it is "H".
You then go back to the Astor rule table and select the line that reads "JointsGuiAllowedSections". You will the copy line 31 at the end of the table and simply change the O to an H. Make sure to also change the KEY number to 99999 to make sure it isn't overlapping anything.
Close Advance manager, update defaults and you will have access to the new category. You can add any category to any macro that way.