The 17-year-olds appeared for a bail hearing on Tuesday but their lawyers made no request to have them released on bond.
They will return to court April 29 when the next steps in the process will be determined.
Crown prosecutor Hippolyte Brin says the accused could face a preliminary hearing before a youth court judge, a trial before a judge alone or a trial before a judge and jury.
The youths face three charges each of premeditated murder and three of conspiracy to commit murder.
Two sisters aged 17 and 22 were found dead in a residence last month along with the younger girl's 17-year-old boyfriend.
The Crown has said it wants the accused to be sentenced as adults if they are convicted.