To facilitate local involvement and flexibility in responding to the problem of crime in their communities and to permit a locally designed community-based probation services agency that will fit its needs, any city, county or combination thereof may, and any city, county or combination thereof that is required by § 53.1-82.1 to file a community-based corrections plan shall establish a system of community-based services pursuant to this article. This system is to provide alternatives for (i) offenders who are convicted and sentenced pursuant to § 19.2-303.3 and who are considered suitable candidates for probation services that require less than incarceration in a local correctional facility and (ii) defendants who are provided a deferred proceeding and placed on probation services. Such services may be provided by qualified public agencies or by qualified private agencies pursuant to appropriate contracts.