Yes, you can!

There is an option called "Max-Limit" that can be enabled for your account from our end. 
On enabling this option, the number of messages that can be sent to a particular number within 24 hour will be limited to only the number of messages specified in "Max-Limit"

For example:
If "Max-Limit" is enabled with the number "2" specified, then from your username, I would only be able to send a maximum on 2 messages to the number 998877xxyy.
Once the 24 hours is done, the clock will reset and the max-limit will refresh for that number on that username.

If this is something that will work for you, we can have this enabled for you right away. Just drop us an email to : and we will have this sorted for you.