Yes. In Pulse SMS, these are pinned conversations. To pin a conversation to the top of the list, you have two options:
- Long-press the conversation, tap the 3-dot menu on the top right, and select "Pin/Unpin Conversation".
- Open the conversation, hit the 3-dot overflow menu on the top right corner, and select Conversation settings or Group settings. On the next screen, enable Pin Conversation.
Apart from individual conversations, Pulse SMS also allows you to pin group conversations.