Not in the sense you're hoping for. You're not going to be able to do an away rotation at another random IR program for the purposes of auditioning for fellowship.
1) that would leave your home program down an upper level resident for a substantial amount of time
2) the amount of paperwork needed to be done to get you credentialed to actually scrub in on cases would overwhelmingly not be worth it for your program or the away place.
3) In instances where residency programs send residents on established out-rotations (e.g. peds, country hospital for trauma, etc...), the home program pays the away-site to teach/train those residents. Your program would likely have to cough up funds to send you out.
As for your strategy, it's no different then pre-IR pathway. Get letters from your home IR's, do some IR research there if possible, make some connections through SIR, and otherwise just do a good job (to generate a strong DR PD letter).