Can I tell a requesting station to ignore a single provider?

[enderland]

I have a small outpost where I make empty barrels as well as request them, so that it serves as an unload location for all finished barrels across the network (and makes more if needed). There are two stations there, one for requesting and one for providing barrels.

However I've realized recently that this causes trains to loop, from the provider there to its requestor. I am wondering how to stop this from happening. Is there a way I can tell the requesting station to ignore the provider there, or otherwise stop this?

[Optera]

Using different train sizes is the only way to block certain provider-requester combinations.

Collecting empty barrels back to one outpost is a useless delivery.
Outposts requesting filled barrels should provide emptied barrels with higher priority than the stop producing new barrels. That way used barrels will always be prioritized and barrel production is only used if there are not enough barrels in circulation.

[enderland]

Using different train sizes is the only way to block certain provider-requester combinations.

Collecting empty barrels back to one outpost is a useless delivery.
Outposts requesting filled barrels should provide emptied barrels with higher priority than the stop producing new barrels. That way used barrels will always be prioritized and barrel production is only used if there are not enough barrels in circulation.

Doh. that's a good point, that works fine