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A workflow can contain multiple trigger nodes but with each execution, only one of them will execute depending on the triggering event.
Instead of having multiple triggers, you could loop through a list of RSS feed urls every 5 minutes using Loop Over Items node (previously called Split in Batches) like in this template here: Get data from multiple RSS feeds to Telegram | n8n workflow template
There’s another post on a similar topic discussing different setups:
Hope these help and feel free to follow up with more specific questions for your usecase