– All prefixes are from jkt, there is community 65000:1040
– All prefixes from Bali, without community

– Bali ISP wants to send prefix to jkt, install community 65000:2040
– Bali ISP doesn’t want to accept Prefixs from jkt, settings a rule on the router for the DENY prefix with community 65000:1040

Sample case:

Bali ISP only wants the Bali prefix.
– deny prefix   with community 65000:1040
– advertise to Route Server without additional community

Bali ISP wants the prefix jkt and wants to advertise to jkt (for example, so that everything is symmetrical via iix)
– accept all prefixes from Route Server (without community and community 65000:1040)
– advertise to Route Server with community 65000:2040

Bali ISP wants to advertise to JKT but doesn’t want to accept prefixes from JKT.
– deny prefix with community 65000:1040
– advertise to Route Server with community 65000:2040

These 3 cases can be carried out by the ISP without interference from Noc IIX Bali.