Thanks for the responses.

@dchky: The mere fact that Conversations is not open, means there is little to nothing than can be done with it, for now.

@fahadj2003: For us here in the Philippines, it can be an inconvenience, since we have these so-called unlimited texting plans, available to most, if not all, providers.

Anyway, looks like the ideal solutions would be to wait for an application that does it, or I'll go and write one.