You can:
A) Bridge the topic to a queue and reconfigure your subscribers to read from the queue. Queues behave differently to topics in that a message is only obtained by one subscriber rather than all.
B) Create a number of durable subscribers on the topic with selectors that divide messages between the durables. E.g. If a message has a property 'id' that is sequentially increasing:
create durable topic DURABLENAME1 selector="(id - 2 * (id / 2)) = 0"
create durable topic DURABLENAME2 selector="(id - 2 * (id / 2)) = 1"
The selector is just a modulo so half the messages will go on one durable, and half on the other.