Peace be upon you. It is permissible to mourn for martyrs other than Hussein and the Ahlul Bayt. According to Grand Ayatollah Sistani, it is allowed. Source: [Commentary on Al-Urwah Al-Wuthqa, Vol. 1, Prohibited Acts of Burial, Section 3](https://www.sistani.org/arabic/book/22/1738/). Grand Ayatollah Khamenei also states that there is no objection to it. Source: [Special Inquiry](https://www.islamq2a.com/masdar/969.png). May you be successful in all good.