Cranford, New Jersey-based The Continuum Group Inc reports that its Enteractive Inc unit has agreed in principle to combine with Sonic Images Productions Inc, Washington, DC developer of music and educational multimedia software. The equity in the combined company will be owned by former shareholders of Sonic and by Continuum, with warrants to be held by existing and new investors in the venture. The merger is expected to be completed next month or the month after, Continuum noted.