It's usually much easier to switch specialty areas if you have a solid ICU background... much easier than going the 'other way' and trying to get into ICU from another area. So that is definitely points in your favor!
However, switching specialties will require additional training & achieving a whole different set of competencies. Employers may be reluctant to do this on a part-time basis because it could take forever - and may not seem like a good return on investment for the new employer because of the limited amount of time you would be available. So,it may be a good idea to offer to increase your work schedule during the time required to accomplish training - even if you have to set a time limit ... e.g., the first 6 months.
Best of luck to you - it takes a special person to work hospice.